JP2015511077A - Multi-user parallel channel access in WLAN systems - Google Patents

Abstract

The method and apparatus includes multi-user parallel channel access (MU-PCA) using transmission and / or reception with symmetric bandwidth in downlink (DL), uplink (UL), or combined DL and UL. And / or single user parallel channel access (SU-PCA). SU-PCA and MU-PCA can support unequal modulation and coding schemes (MCS) and unequal transmit power. Medium access control (MAC) layer, physical layer (PHY), and hybrid and PHY layer methods and procedures may be used with UL, DL, and combined UL using transmission and / or reception with symmetric bandwidth. DL SU-PCA and MU-PCA can be supported. MU-PCA and / or SU-PCA are MAC and PHY layer designs and procedures for downlink, uplink, and combined uplink and downlink using transmit / receive with asymmetric bandwidth Can also be supported.

Description

  The present invention relates to multi-user parallel channel access in WLAN systems.

CROSS REFERENCE TO RELATED APPLICATIONS This application is based on US Provisional Patent Application No. 61 / 605,538 filed on Mar. 1, 2012, U.S. Provisional Application No. 61 / 669,505 filed on July 9, 2012. , And claims the benefit of US Provisional Application No. 61/684051, filed Aug. 16, 2012, the contents of which are hereby incorporated by reference.

  A wireless local area network (WLAN) in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. An AP may have access or interface to a distributed system (DS) or another type of wired / wireless network that carries traffic in and out of the BSS. Traffic originating from outside the BSS and destined for the STA can arrive through the AP and can be delivered to the STA. Traffic originating from the STA and destined for a destination outside the BSS can be delivered to each destination after being transmitted to the AP. Traffic between STAs in the BSS can also be sent through the AP, the source STA can send traffic to the AP, and the AP can deliver traffic to the destination STA. Such traffic between STAs within the BSS may be considered peer-to-peer traffic. Such peer-to-peer traffic is directly between the source STA and the destination STA using, for example, DLS using 802.11e direct link setup (DLS) or 802.11z tunnel DLS (TDLS). Can also be sent to. WLANs in independent BSS (IBSS) mode may not have APs, and STAs can communicate directly with each other. This mode of communication may be referred to as “ad hoc” mode communication.

  In operation in 802.11 infrastructure mode, an AP can transmit a beacon via a fixed channel called a primary channel. This channel is 20 megahertz (MHz) wide and is the operating channel of the BSS. This channel is also used by the STA to establish a connection with the AP. The basic channel access mechanism in 802.11 systems is carrier sense multiple access (CSMA / CA) with collision avoidance. In this mode of operation, any STA including the AP can sense the primary channel. If the channel is detected and busy, the STA can back off. Thus, within a given BSS, only one STA can be transmitted at any given time.

  In 802.11n, high throughput (HT) STAs can also use 40 MHz wide channels to communicate. This can be achieved by combining the primary 20 MHz channel with another adjacent 20 MHz channel to form a 40 MHz wide channel. In 802.11ac, a very fast throughput (VHT) STA can support 40 MHz, 80 MHz, and 160 MHz wide channels. The 40 MHz and 80 MHz channels can be formed by combining continuous 20 MHz channels as in 802.11n above, while the 160 MHz channel combines eight consecutive 20 MHz channels, or two non-contiguous 80 MHz channels. Can be formed by either combining (80 + 80 configuration). For the “80 + 80” configuration, the data may be passed through a segment analyzer that can split it into two streams after channel coding. Inverse Fast Fourier Transform (IFFT) and time domain processing may be performed separately for each stream. The stream can then be mapped to two channels and data can be sent out. On the receiving side, this mechanism can be reversed, and the combined data can be sent to the medium access control (MAC) layer.

  For operation in sub-1 GHz mode (eg, 802.11af and 802.11ah), channel operating bandwidth may be reduced when compared to 802.11n and 802.11ac. 802.11af can support 5 MHz, 10 MHz, and 20 MHz wide bands in TV white space (TVWS), while 802.11ah can support 1 MHz, 2 MHz, 4 MHz, and 8 MHz in non-TVWS. Some STAs in 802.11ah may be considered sensors with limited capabilities and may only support a 1 MHz transmission mode.

  WLAN systems using multiple channel widths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. Yes, there can be a primary channel. The bandwidth of the primary channel may be limited by STAs that support the minimum bandwidth mode of operation. In the 802.11ah example, if there are STAs that only support 1 MHz mode, the primary channel is 1 MHz wide even though APs and other STAs in the BSS can support 2 MHz, 4 MHz, 8 MHz, and 16 MHz operating modes. Can be. All carrier sensing and NAV settings may depend on the status on the primary channel. For example, if a primary channel is busy because a STA that supports only 1 MHz mode of operation is transmitting to the AP, the entire available frequency band may be available, even though most of it is idle. It can be considered busy. In 802.11ah and 802.11af, all packets may be transmitted using a clock that may be downclocked 4 or 10 times compared to the 802.11ac specification.

  In the United States, the available frequency bands that can be used by 802.11ah can be from 902 MHz to 928 MHz, in Korea from 917.5 MHz to 923.5 MHz, and in Japan from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah can be from 6 MHz to 26 MHz, depending on the country code.

  In addition, in the 802.11 standard, only one STA may be transmitted at any given time within the BSS. On the DL (ie, when the AP sends to the STA), if multi-user multiple-input multiple-output (MU-MIMO) is not used, the AP can switch packets with only one STA at any given time. It can be performed. When multi-user MIMO (MU-MIMO) is used, the AP can transmit to multiple STAs. However, all STAs participating in MU-MIMO may be communicating on the same band that can be limited by the STA with the minimum operating bandwidth. In this scenario, the remaining frequency bandwidth may remain idle even though it may be available from the AP and other STAs.

  The method and apparatus includes multi-user parallel channel access (MU-PCA) using transmission and / or reception with symmetric bandwidth in downlink (DL), uplink (UL), or combined DL and UL. And / or single user parallel channel access (SU-PCA). SU-PCA and MU-PCA can support unequal modulation and coding schemes (MCS) and unequal transmit power. Medium access control (MAC) layer, physical layer (PHY), and hybrid and PHY layer methods and procedures may be used with UL, DL, and combined UL using transmission and / or reception with symmetric bandwidth. DL SU-PCA and MU-PCA can be supported. MU-PCA and / or SU-PCA are MAC and PHY layer designs and procedures for downlink, uplink, and combined uplink and downlink using transmit / receive with asymmetric bandwidth Can also be supported.

  A more detailed understanding can be obtained from the following description, given by way of example, in conjunction with the accompanying drawings.

1 is a system diagram of an example communication system in which one or more disclosed embodiments may be implemented. FIG. 1B is a system diagram of an example wireless transmit / receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A. FIG. 1B is a system diagram of an example radio access network and an example core network that may be used within the communications system illustrated in FIG. 1A. FIG. It is a figure which shows the example of WLAN BSS containing AP and four STA. It is a figure which shows the example of the frequency resource consumption in the WLAN system which uses multiple channel widths. FIG. 4 is a diagram illustrating an exemplary frame format of a group transmission request (G-RTS) control frame. FIG. 4 is a diagram illustrating an exemplary frame format of a group transmission ready (G-CTS) control frame. FIG. 6 illustrates an exemplary frame format for a multi-user parallel channel access (MU-PCA) management (MPM) frame. FIG. 6 illustrates an exemplary medium access control (MAC) scheme for enabling DL MU-PCA using control frames over multiple channels. FIG. 2 illustrates an example MAC scheme for a single downlink (DL) MU-PCA using G-RTS and G-CTS over a primary channel. FIG. 3 illustrates an example MAC scheme for enabling DL MU-PCA using control frames over multiple channels and also enabling MU-PCA for WiFi STAs. FIG. 3 illustrates an example MAC scheme for enabling DL MU-PCA using control frames and block acknowledgment (BA). FIG. 4 illustrates an exemplary frame format for an uplink request frame (ULR). FIG. 3 is a diagram illustrating an exemplary frame format of a group polling (G-Poll) frame. FIG. 3 illustrates an example MAC scheme that supports uplink (UL) MU-PCA for data without severe delay bounds. FIG. 3 illustrates an example MAC scheme that supports UL MU-PCA for data with severe delay bounds. FIG. 2 illustrates an example MAC scheme that supports UL MU-PCA for data in which ULR packets are sent in order. FIG. 3 illustrates an example MAC scheme that supports UL MU-PCA for data with mixed delay requirements. It is a figure which shows the example of the MAC system which supports combined MU-PCA of DL and UL. FIG. 6 shows an exemplary flow diagram of a method for combined DL and UL MU-PCA performed by a STA in a BSS system. FIG. 6 illustrates an example MAC scheme that supports combined UL and DL MU-PCA. FIG. 6 illustrates an exemplary MAC scheme in which UL MU-PCA transmission is initiated by a ULR that is transmitted sequentially over a primary channel. FIG. 6 illustrates an example MAC scheme that enables combined DL / UL MU-PCA using control frames over multiple channels and also enables MU-PCA for legacy WiFi STAs. . FIG. 4 is an exemplary transmission flow diagram with users capable of channel aggregation. FIG. 3 illustrates an example physical (PHY) layer scheme in which a physical layer convergence protocol (PLCP) header is transmitted over separate frequency channels. FIG. 6 is a diagram illustrating an example of a DL transmission flow diagram through a hybrid aggregated channel at an AP. FIG. 3 illustrates an exemplary flow of PLCP protocol data unit (PPDU) transmission over a channel that includes a hybrid aggregated channel. FIG. 4 illustrates another example flow of PPDU transmission over a channel that includes a hybrid aggregated channel. FIG. 3 is a flow diagram of an example method that uses layer mapping to map N MAC packets to K layers. It is a figure which shows the example of the PHY layer system which has three MU-PCA users. It is a figure which shows the example of a PHY-layer system with two MU-PCA users. FIG. 3 is a diagram illustrating an example of a PHY layer scheme using an exemplary STF format for MU-PCA transmission. FIG. 2 is a diagram illustrating an exemplary PHY layer scheme using a PPDU that uses a long preamble. FIG. 3 is an exemplary transmission flow diagram for transmitting DL communication. FIG. 6 is an exemplary transmission flow diagram for transmitting UL communications. FIG. 6 is an exemplary transmission flow diagram for receiving UL communications. FIG. 3 is an exemplary transmission flow diagram for transmitting DL communication.

  FIG. 1A is a diagram of an example communications system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may allow multiple wireless users to access such content through sharing of system resources including wireless bandwidth. For example, the communication system 100 may include code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), and single carrier FDMA (SC-FDMA), such as 1 or Multiple channel access methods may be utilized.

  As shown in FIG. 1A, a communication system 100 includes a wireless transmit / receive unit (WTRU) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network 106, a public switched telephone network (PSTN) 108, and the Internet 110. , And other networks 112, it will be appreciated that the disclosed embodiments are intended for any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, WTRUs 102a, 102b, 102c, 102d may be configured to transmit and / or receive radio signals, such as user equipment (UE), mobile stations, fixed or mobile subscriber units, pagers, cellular telephones, A personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a home appliance, and the like can be included.

  The communication system 100 may also include a base station 114a and a base station 114b. Each of the base stations 114a, 114b is configured to facilitate at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks such as the core network 106, the Internet 110, and / or other networks 112. It can be any type of device configured to interface with one wirelessly. By way of example, base stations 114a, 114b can be base transceiver stations (BTS), Node B, eNode B, home Node B, home eNode B, site controller, access point (AP), wireless router, etc. . Although base stations 114a, 114b are each shown as a single element, it will be appreciated that base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

  Base station 114a may be part of RAN 104, and RAN 104 may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), radio network controller (RNC), relay node, etc. . Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals within a particular geographic region, sometimes referred to as a cell (not shown). The cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, ie, one for each sector of the cell. In another embodiment, the base station 114a may utilize multiple input multiple output (MIMO) technology and thus may utilize multiple transceivers per sector of the cell.

  Base stations 114a, 114b may communicate with one or more of WTRUs 102a, 102b, 102c, 102d over air interface 116, which may be connected to any suitable wireless communication link (eg, radio frequency (RF), Microwave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

  More specifically, as mentioned above, the communication system 100 may be a multiple access system, utilizing one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. obtain. For example, the base station 114a in the RAN 104 and the WTRUs 102a, 102b, 102c may establish a universal mobile communication system (UMTS) terrestrial radio access (WBMS) using wideband CDMA (WCDMA®) ( Wireless technologies such as UTRA) may be implemented. WCDMA may include communication protocols such as high-speed packet access (HSPA) and / or evolved HSPA (HSPA +). HSPA may include high speed downlink packet access (HSDPA) and / or high speed uplink packet access (HSUPA).

  In another embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may establish an evolved UMTS ground where the air interface 116 may be established using Long Term Evolution (LTE) and / or LTE Advanced (LTE-A). A radio technology such as radio access (E-UTRA) may be implemented.

  In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may be IEEE 802.16 (ie, global interoperability for microwave access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, provisional. Standard 2000 (IS-2000), provisional standard 95 (IS-95), provisional standard 856 (IS-856), global system for mobile communication (GSM (registered trademark)), high-speed data rate (EDGE) for GSM evolution , GSM EDGE (GERAN), etc. may be implemented.

  The base station 114b of FIG. 1A can be, for example, a wireless router, a home Node B, a home eNode B, or an access point, to facilitate wireless connectivity in local areas such as work, home, vehicle, campus, etc. Any suitable RAT may be utilized. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, base station 114b and WTRUs 102c, 102d may implement a wireless technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, base station 114b and WTRUs 102c, 102d may utilize a cellular-based RAT (eg, WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.) to establish a picocell or femtocell. . As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Accordingly, the base station 114b may not need to access the Internet 110 via the core network 106.

  The RAN 104 may communicate with a core network 106, such that the core network 106 provides voice, data, application, and / or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. It can be any type of network configured. For example, the core network 106 may provide call control, billing services, mobile location based services, prepaid calls, Internet connectivity, video delivery, etc. and / or perform high level security functions such as user authentication. . Although not shown in FIG. 1A, it will be appreciated that the RAN 104 and / or core network 106 may communicate directly or indirectly with other RANs that utilize the same RAT as the RAN 104 or a different RAT. For example, in addition to being connected to a RAN 104 that may utilize E-UTRA radio technology, the core network 106 may also communicate with another RAN (not shown) that utilizes GSM radio technology.

  The core network 106 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit switched telephone network that provides basic telephone service (POTS). Internet 110 is an interconnected computer network that uses common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and Internet Protocol (IP) within the TCP / IP Internet Protocol Suite. A global system of devices can be included. Other networks 112 may include wired or wireless communication networks owned and / or operated by other service providers. For example, the other network 112 may include another core network connected to one or more RANs that may utilize the same RAT as the RAN 104 or a different RAT.

  Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capability, i.e., the WTRUs 102a, 102b, 102c, 102d are for communicating with different wireless networks over different wireless links. Multiple transceivers may be included. For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a that may utilize cellular-based radio technology and with a base station 114b that may utilize IEEE 802 radio technology.

  FIG. 1B is a system diagram of an example WTRU 102. As shown in FIG. 1B, the WTRU 102 includes a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, and a non-removable memory 130. , Removable memory 132, power supply 134, global positioning system (GPS) chipset 136, and other peripheral devices 138. It will be appreciated that the WTRU 102 may include any sub-combination of the above elements while remaining consistent with embodiments.

  The processor 118 may be a general purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC). ), Field programmable gate array (FPGA) circuits, any other type of integrated circuit (IC), state machine, and the like. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. 1B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

  The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (eg, base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In another embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and receive both RF and optical signals. It will be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

  In addition, in FIG. 1B, the transmit / receive element 122 is shown as a single element, but the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may utilize MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (eg, multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

  The transceiver 120 may be configured to modulate the signal transmitted by the transmit / receive element 122 and demodulate the signal received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode functionality. Thus, transceiver 120 may include multiple transceivers to allow WTRU 102 to communicate via multiple RATs, such as, for example, UTRA and IEEE 802.11.

  The processor 118 of the WTRU 102 may be coupled to and from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (eg, a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). User input data may be received. The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, processor 118 may obtain information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. Non-removable memory 130 includes random access memory (RAM), read only memory (ROM), hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may obtain information from memory located on a server or home computer (not shown), etc., rather than memory physically located on the WTRU 102, and store data on them. Can be stored.

  The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control power to other components in the WTRU 102. The power source 134 can be any suitable device for powering the WTRU 102. For example, the power supply 134 may be one or a plurality of dry cells (eg, nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel hydride (NiMH), lithium ion (Li-ion), etc.), solar cells, fuel cells, etc. Can be included.

  The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (eg, longitude and latitude) regarding the current location of the WTRU 102. In addition to or instead of information from the GPS chipset 136, the WTRU 102 may receive location information on the air interface 116 from a base station (eg, base stations 114a, 114b) and / or more than one near Based on the timing of the signal received from the base station, its own position can be determined. It will be appreciated that the WTRU 102 may obtain location information using any suitable location determination method while remaining consistent with embodiments.

  The processor 118 may be further coupled to other peripherals 138, which may include one or more software modules and / or software that provide additional features, functions, and / or wired or wireless connectivity. A hardware module may be included. For example, peripheral devices 138 include accelerometers, e-compasses, satellite transceivers, digital cameras (for photography or video), universal serial bus (USB) ports, vibration devices, television transceivers, hands-free headsets, Bluetooth (registered) Trademark) module, frequency modulation (FM) radio unit, digital music player, media player, video game player module, Internet browser, and the like.

  FIG. 1C is a system diagram of the RAN 104 and the core network 106 according to an embodiment. The RAN 104 may be an access service network (ASN) that communicates with the WTRUs 102a, 102b, 102c over the air interface 116 utilizing IEEE 802.16 radio technology. As described further below, communication links between different functional entities of the WTRUs 102a, 102b, 102c, the RAN 104, and the core network 106 may be defined as reference points.

  As shown in FIG. 1C, the RAN 104 may include base stations 140a, 140b, 140c and an ASN gateway 142, but the RAN 104 may be connected to any number of base stations and ASNs while remaining consistent with the embodiment. It will be understood that a gateway may be included. Base stations 140a, 140b, 140c may each be associated with a particular cell (not shown) in RAN 104, each one or more for communicating with WTRUs 102a, 102b, 102c over air interface 116. A transceiver may be included. In one embodiment, the base stations 140a, 140b, 140c may implement MIMO technology. Thus, the base station 140a can transmit radio signals to and receive radio signals from the WTRU 102a using, for example, multiple antennas. Base stations 140a, 140b, 140c may also provide mobility management functions such as handoff triggering, tunnel establishment, radio resource management, traffic classification, quality of service (QoS) policy enforcement. The ASN gateway 142 may serve as a traffic aggregation point and may be responsible for paging, subscriber profile caching, routing to the core network 106, and the like.

  The air interface 116 between the WTRUs 102a, 102b, 102c and the RAN 104 may be defined as an R1 reference point that implements the IEEE 802.16 specification. In addition, each of the WTRUs 102a, 102b, 102c may establish a logical interface (not shown) with the core network 106. The logical interface between the WTRUs 102a, 102b, 102c and the core network 106 may be defined as an R2 reference point, which may be used for authentication, authorization, IP host configuration management, and / or mobility management.

  The communication link between each of the base stations 140a, 140b, 140c may be defined as an R8 reference point that includes a protocol for facilitating WTRU handover and transfer of data between base stations. The communication link between the base stations 140a, 140b, 140c and the ASN gateway 142 may be defined as an R6 reference point. The R6 reference point may include a protocol for facilitating mobility management based on mobility events associated with each of the WTRUs 102a, 102b, 102c.

  As shown in FIG. 1C, the RAN 104 may be connected to the core network 106. The communication link between the RAN 104 and the core network 106 may be defined as an R3 reference point that includes protocols for facilitating data transfer and mobility management functions, for example. The core network 106 may include a mobile IP home agent (MIP-HA) 144, an authentication authorization charging (AAA) server 146, and a gateway 148. Although each of the above elements is shown as part of the core network 106, it will be understood that any one of these elements may be owned and / or operated by entities other than the core network operator.

  The MIP-HA may be responsible for IP address management and may allow the WTRUs 102a, 102b, 102c to roam between different ASNs and / or between different core networks. The MIP-HA 144 may provide access to a packet switched network such as the Internet 110 to the WTRUs 102a, 102b, 102c to facilitate communication between the WTRUs 102a, 102b, 102c and the IP enabled device. The AAA server 146 may be responsible for user authentication and user service support. Gateway 148 may facilitate inter-network connections with other networks. For example, the gateway 148 may provide access to a circuit switched network, such as the PSTN 108, to the WTRUs 102a, 102b, 102c to facilitate communication between the WTRUs 102a, 102b, 102c and conventional landline communication devices. In addition, gateway 148 may provide access to other networks 112 to WTRUs 102a, 102b, 102c, which may include other wired or wireless networks owned and / or operated by other service providers. .

  Although not shown in FIG. 1C, it will be appreciated that the RAN 104 may be connected to other ASNs and the core network 106 may be connected to other core networks. Communication links between the RAN 104 and other ASNs may be defined as R4 reference points, which may include protocols for coordinating the mobility of the WTRUs 102a, 102b, 102c between the RAN 104 and other ASNs. . Communication links between the core network 106 and other core networks may be defined as R5 references, which may include a protocol for facilitating an inter-network connection between the home core network and the visited core network. .

  In a multi-channel width WLAN system, if the communicating STAs may only be able to transmit and receive over a small portion of the available bandwidth, the 802.11 standard will determine the remaining available frequency bandwidth. It may be defined that the AP and other STAs remain idle throughout the BSS even though they can utilize that portion of available bandwidth. As a result, the resources in such a BSS are not fully utilized and may be wasted. This problem may exist in any WLAN system that uses multiple channel widths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, with some STAs in the BSS having minimal 1 MHz operation Only mode is supported.

FIG. 2A shows an example of a WLAN BSS 200 that includes an AP 204 and _four STAs: STA1 202 ₁ , STA2 202 ₂ , STA3 202 ₃ , and STA4 202 ₄ . FIG. 2B illustrates an exemplary MAC scheme with frequency resource consumption in a WLAN system using multiple channel widths, eg, WLAN BSS 200 of FIG. 2A. FIG. 2B illustrates the four channels 218 ₁ performed by the AP and STA of FIG. 2A _{. . . 4} shows the transmission over time. In all diagrams illustrating an exemplary MAC scheme, such as FIG. 2B, the entity performing the transmission (eg, AP, STA1, STA2, STA3, or STA4) is indicated with a subscript for each transmission. The channel can be any bandwidth and channel 218 _{1. . . 4} can be continuous or discontinuous, but channel 218 _{1. . .} Each ₄ is 1MHz wide, that the channel 218 ₁ is the primary channel, for purposes of explanation, it is assumed in all the figures. In addition, AP 204 and STA 202 in FIG _{. . . 4} can operate over more or less than 4 channels, but any of the channels can be continuous or discontinuous and can be located in the same band or in different frequency bands. Also, the MAC scheme shown in the figure is an example, and each feature or element (eg, type message of transmission) is another feature and element of the MAC scheme being described (eg, other type of message transmission). Can be used alone, or in various combinations with or without other features and elements.

In the example of FIGS. 2A and 2B, AP 204 can enable 1 MHz, 2 MHz, and 4 MHz operating modes, STA1 202 ₁ and STA4 202 ₄ can enable 1 MHz mode, and STA2 202 ₂ It is assumed that 1 MHz, 2 MHz, and 4 MHz modes can be enabled, and STA3 202 ₃ can enable 1 MHz and 2 MHz modes. If STA2 202 ₂ and AP 204 to communicate, for example, the acknowledgment (ACK) transmission _{208 STA2} data transmission _{206 AP} from AP 204 to STA2 202 _2, and the STA2 202 ₂ to AP 204, the packet, four channels 218 _{1 . . .} Sent over the available frequency bandwidth including all _four . Data transmission 210 _STA3 to _AP 204 and ACK 212 _AP to STA3 202 ₃ are limited to ₂ MHz or channels 218 _1-2 . Similarly, ACK216 _AP to data transmission _{213 STA1,} and STA1 202 ₁ to AP 204, are limited 1MHz or channels 218 _1,. The unused channel is the idle frequency band 220. Thus, in this example, when STA1 202 ₁ or STA3 202 ₃ communicates with AP 204, at least half of the available bandwidth is idle, even though other STAs in the BSS may have packets to transmit. Or, in the case of STA1 202 ₁ , three quarters may be idle. This can limit the capacity of the BSS and can be a bottleneck, but it can operate especially on the sub 1 GHz band and has much smaller bandwidth compared to 802.11n and 802.11ac. This is not the case with technologies such as 802.11af and 802.11ah.

  In an example use case such as a smart meter, an AP may need to support up to 6000 STAs within one BSS in 802.11ah. Due to the CSMA / CA nature of the WLAN's medium access control (MAC) layer, a huge number of users can cause significant congestion and delay, and therefore very low effective throughput due to packet collisions within the BSS. May bring. As explained above, in the case of multi-user parallel channel access (MU-PCA) in a WLAN system using multiple channel widths, some or sometimes most of the bandwidth available in the BSS is available bandwidth. May be wasted due to media access by a single STA that operates only on that part of the network. In addition, if the WLAN system must support up to 6000 STAs within a single BSS, congestion, delay, and not equal throughput are brought about by the CSMA / CA nature of the 802.11 MAC layer function. obtain.

  Can be continuous or discontinuous, such as within the same band or another band (e.g., 2.4 GHz Industrial Science and Medical (ISM) band, less than 6 GHz band, 60 GHz band, less than 1 GHz band, 3.5 GHz band, or 45 GHz band, etc. Enabling parallel media access between multiple STAs that support different operating channel widths on available bandwidth that can be placed in any combination) can improve frequency bandwidth utilization and efficiency, A huge number of STAs, for example, up to 6000 STAs can be supported.

  In the 80 + 80 channel configuration, for single STA access, non-contiguous aggregation can be defined in 802.11ac, and data to / from a single STA can be divided into two streams, each with 2 It can be transmitted individually on one of the two non-contiguous 80 MHz channels. This allows packets to / from multiple STAs to be transmitted simultaneously to / from APs on multiple frequency bands using one STA on one or multiple channels, Channel width and channel width may depend on the operating bandwidth supported by the STA and AP. In this way, through multi-user parallel channel access (MU-PCA), the number of supported STAs can be increased and resource utilization can be significantly improved. In addition, single-user parallel channel access (SU-PCA) over a number of consecutive or non-consecutive channels in the DL or UL direction, or in the transmission or reception of direct link setup (DLS) or tunnel direct link setup (TDLS) ) Or a MU-PCA session can be assigned to a single STA to allow single user channel aggregation, which is a special case of MU-PCA.

  MU-PCA can be achieved by utilizing transmission / reception with symmetric bandwidth. The term “symmetric bandwidth” means that the AP and STA use the same bandwidth for transmission and reception. The AP integrates the PHY layer design enhancement, in which case the impact on the non-AP STA hardware is minimal. MU-PCA can also be achieved by utilizing transmission / reception with asymmetric bandwidth. The term “asymmetric bandwidth” means that the AP uses the broadband to transmit and receive, and the STA uses the relatively narrow frequency band to transmit and receive. In order to support MU-PCA, PHY layer changes may be made in both AP STAs and non-AP STAs.

  MU-PCA can use transmit / receive with symmetric bandwidth, and can use MAC layer designs and procedures, and PHY layer designs and procedures. The MAC layer design and procedure is from a scheme that allows a single downlink MU-PCA, a single uplink MU-PCA, a combined DL / UL MU-PCA, and / or a MU-PCA retransmission in case of transmission errors. Can be. PHY layer design and procedures can exist in the AP to support MU-PCA at the AP. Since an AP can support multiple simultaneous connections to different STAs, the PHY layer design and procedure can affect the AP's hardware, but (non-AP) STAs can only operate on channels of operating bandwidth that they already support When using to communicate with an AP, it cannot be affected.

  In the MAC scheme, it can be assumed that there is one primary channel for each BSS. The primary channel can be of any bandwidth and can be continuous or discontinuous with other channels. If an AP STA and / or a non-AP STA is not actively transmitting, receiving, or in a dormant or other power saving mode (eg, according to a power saving mode protocol / procedure), Can be monitored. As described herein, the primary channel is assumed to be channel 1 unless otherwise indicated.

  STAs participating in MU-PCA may be organized into groups in either a pre-determined manner or an ad hoc manner for both UL and DL transmissions, or combined UL and DL transmissions. The STA grouping for UL and the STA grouping for DL may be the same or different. STAs can be grouped together according to many different criteria, such as, for example, operating channel width, received power as in AP, RSSI, QoS priority, propagation delay, synchronization, or buffered packet length. Can be With adjustments, the grouped STAs can utilize all or at least most of the available frequency bandwidth. For example, if the entire available frequency band is 4 MHz, whether continuous or non-continuous, a possible STA group can either have 4 nodes that only support 1 MHz operation mode, or 2 nodes that only support 1 MHz operation mode. And a node that supports a 2 MHz mode of operation.

  MU-PCA may be provided simultaneously to multiple STAs via multiple channels with different bandwidths, which may be continuous or non-contiguous and may be the same frequency band or different frequency bands (e.g., Any combination of 2.4 GHz ISM band, 3.5 GHz band, less than 6 GHz band, 45 GHz band, 60 GHz band, or less than 1 GHz band). In addition, via a number of continuous or discontinuous channels in the DL direction, UL direction, or combined UL and DL directions, or in the transmission or reception of direct link setup (DLS) or tunnel direct link setup (TDLS) In order to enable SU-PCA, a MU-PCA session may be assigned to a single STA.

  Single DL MU-PCA may be supported by the MAC scheme by using packet exchange such as group transmission request (G-RTS), group transmission ready (G-CTS), and MU-PCA management (MPM) . Examples of such MAC schemes are shown in FIGS. 6-9 and are described in detail below, but each feature or element shown for example purposes is another feature of the described MAC scheme. And without elements, or in various combinations with or without other features and elements. In the following, the format of control frames such as G-RTS, G-CTS, and MPM, and transmission of control frames will be described. The example frames shown in FIGS. 3, 4, and 5 do not show all possible fields that may be included in the frame. For example, the MAC header and frame body may include other fields not shown. Further, the fields can appear in any order and may not necessarily be in the order shown. For example, the type, subtype, and destination address (DA) fields may not appear in the MAC header in the order shown.

FIG. 3 shows an exemplary frame format for the G-RTS control frame 300. The G-RTS frame 300 can include a MAC header 302, a frame body 304, and a frame check sequence (FCS) 306. The frame body 304 includes a MAP field 308 and a channel assignment field 310 _{. . . N} and an additional information (Info) field 312 may be included. The MAC header 302 can include, among other things, a type 314, a subtype 316, and a destination address (DA) field 318, other fields not shown. The G-RTS frame 300 can be, for example, a modified version of an RTS frame and can include a frame body 304 that includes channel assignment information. The G-RTS frame 300 may also be implemented as other types of frames, such as action frames, frames without action ACKs, or any other type of management or control frame. The G-RTS frame 300 may also be implemented as an IE, field, or subfield of a management or control frame.

  In the example of FIG. 3, G-RTS frame 300 may be identified as G-RTS frame 300 with MAC header 302, for example, with a type 314 and subtype 316 field in MAC header 302. For example, if the type 314 and subtype 316 fields include bits B2, B3, B4, B5, B6, and B7, the bits are listed in Table 1 to identify the frame as a control type and a G-RTS subtype. Can be set as shown.

  The DA field 318 in the MAC header 302 may be set to be a multicast MAC address if a group of STAs for DL MU-PCA is formed and can be identified by the multicast MAC address. Alternatively, the DA field can be set to be the broadcast address, and the STA for DL MU-PCA is identified in the frame body 304 or by the group ID in the physical layer convergence procedure (PLCP) header (not shown). obtain. If SU-PCA is used, the G-RTS frame 300 may also be sent to the unicast MAC address of the target STA.

The frame body 304 of the G-RTS frame 300 has a channel assignment 3101 for a group of STAs for DL MU-PCA _{. . . N} may be included. The MAP field 308 of the frame body 304 may itself be implemented as any other field or subfield or information element (IE), such as the length of the frame body 304 (ie, channel assignment), and the channel assignment field. 310 _{1. . .} It can be shown that _N number N, ie, how many STAs the G-RTS includes channel assignments. Other additional information fields 312 not described may also be included.

STA channel assignment 310 if DA field 318 is set to be a broadcast address _{. . .} Each of _N may have explicit identification information (ID) for each of the STAs in the DL MU-PCA group, where the ID is, for example, an association ID (AID), a MAC address, or an AP and STA Other types of IDs established / negotiated can be used. If DA field 318 is set to be a multicast address for the group, channel assignment field 310 _{1. . . N} may include the ID for the DL STA implicitly (eg, by the order of the STAs in the MU-PCA group) or explicitly. Each indicated STA may be assigned to one or more continuous or non-contiguous channels. Channel assignment field 310 _{1. . . The} ID used to explicitly indicate the DL MU-PCA group STA in _N may be, for example, an AID, MAC address, or other form of ID negotiated by the AP and STA. Multiple STAs in a MU-PCA group may be assigned to the same channel if the STA enables multi-user multiple-input multiple-output (MU MIMO), in which case the frame body 304 (eg, channel assignment) is: It can also include the number of spatial streams assigned for each of the MU MIMO STAs assigned to the same set of channels.

FIG. 4 shows an exemplary frame format for the G-CTS control frame 400. The G-CTS frame 400 can include a MAC header 402, a frame body 404, and a frame check sequence (FCS) 406. The frame body 404 includes a MAP field 408 and a channel assignment field 410 _{. . . N} and an additional information (Info) field 412 may be included. The MAC header 402 can include, among other things, a type field 414, a subtype field 416, and a DA field 418, other fields not shown. The G-CTS frame 400 may be implemented as a modified version of the CTS frame. The G-CTS frame 400 may also be implemented as other types of frames, such as action frames, no action ACK frames, or any other type of management and control frames.

The frame body 404 is a channel assignment field 410 for STAs participating in UL MU-PCA _{. . . N} may be included. For example, type fields 414 in MAC header 402 and bits B2-B7 in subtype field 416, as shown in Table 2, make G-CTS frame 400 as a control type frame and G-CTS subtype. Can be identified as

  The DA field 418 in the MAC header 402 may be set to be a multicast MAC address representing a group of STAs if a MU-PCA group is formed and can be identified by a multicast MAC address. Alternatively, the DA field 418 may be set to be a broadcast address, and the STA for MU-PCA may be identified in the frame body 404 or by the group ID in the PLCP header (not shown). If SU-PCA is used, the G-CTS frame 400 may be sent to the unicast MAC address of the target STA.

The MAP field 408 may be implemented as part of another field in the frame body 404 or in the MAC header 402 (or PLCP header not shown), and is a channel assignment field for STAs in the G-CTS frame 400 410 _{1. . .} The presence of available information such as _N can be indicated. When used in conjunction with a single DL MU-PCA, the G-CTS frame body 404 may include a MAP element and a channel assignment field 410 _{. . . N} may not be included. Multiple STAs in a MU-PCA group may be assigned to the same channel if the STA enables MU MIMO, in which case the channel assignments in the frame body 404 are assigned to the same set of channels MU MIMO STAs. The number of spatial streams allocated for each of the can also be included.

FIG. 5 shows an exemplary frame format for a MU-PCA management (MPM) frame 500. The MPM frame 500 can include a MAC header 502, a frame body 504, and an FCS 506. The frame body 504 has the following fields: MAP field 508, group ID 514, start time 516, duration 518, MU-PCA selection 520, STA information field 510 corresponding to STA1 to N1 _{. . . N} , and additional information 512 can be included. These fields are described in more detail below.

The MAP field 508 can indicate the type of information included in the MPM 500. For example, the MAP field 508 indicates how many STA information (Info) fields 510 the MPM 500 has _{. . . N} can be indicated. The MAP field 508 may itself be implemented as a field or a subfield of another field. The group ID 514 may indicate an ID of the STA1-N MU-PCA groups that may be determined in advance or formed in an ad hoc manner. The start time field 516 may indicate the start time of the next MU-PCA session, where the MU-PCA session includes a DL or UL or combined DL / UL SU-PCA transmission, DL or UL or combination. DL / UL MU-PCA transmission. The start time may be implicitly defined if, for example, the next frame is transmitted at a set interval, such as a short frame interval (SIFS) interval that starts at the end of the MPM 500. The duration field 518 may indicate the duration of the next MU-PCA session. The duration may be implicitly defined by a value included in the duration field (not shown) of the MAC header 502.

The MU-PCA selection field 520 may indicate the selection of the MU-PCA session, the selection including UL MU-PCA, DL MU-PCA, combined UL / DL MU-PCA. Similarly, MU-PCA selection field 520 may also be used to indicate an equivalent SU-PCA selection when MPM 500 is transmitted to a single STA. Each STA information field 510 _{1. . . N} may include STA1 through N information about the next MU-PCA session. Each STA information field 510 _{1. . . N} may include subfields that contain information (note: subfields are not explicitly shown in FIG. 5). For example, the STA ID subfield may indicate a STA ID that may be implemented as a MAC address, AID, or other ID agreed upon by the AP and the STA. For example, if the MPM is a unicast frame to a specific STA and the MPM is used to initiate a SU-PCA transmission, the STA ID may not be used. In another example, a MU-PCA group is formed, the order of STAs in the MU-PCA group is determined, and each STA belonging to the MU-PCA can know which subfield contains its own information The STA ID subfield may not be used.

  In another example, the channel assignment subfield may indicate the number of channels assigned to the STA and the location of the assigned channel. Channel location may be implemented using parameters such as channel number, center frequency, bandwidth, offset from primary channel, or frequency band, among others. Multiple STAs in a MU-PCA group may be assigned to the same channel if the STA enables MU MIMO, in which case the channel assignment subfield is in each MU MIMO STA assigned to the same set of channels. It can also include the number and / or order of spatial streams assigned to it.

  Control packets such as G-RTS, G-CTS, ACK, and MPM in the context of a single DL MU-PCA may be sent in multiple modes. They are transmitted on each individual channel (eg, as shown in FIGS. 6-9, described in detail below), and all STAs utilizing the channel within the same BSS or overlapping BSS Can provide correct network allocation vector (NAV) settings. On the other hand, if the STA knows a transmission over a larger bandwidth and is able to receive such a transmission, the control frame is modulated (eg, using a larger IFFT) and multiple May be transmitted over multiple channels. For example, if only STAs supporting 2 MHz mode are assigned to operate on channel 2 and channel 3 throughout the network coverage area, for example, G-RTS, G-CTS, and ACK are two channels, For example, it can be transmitted across channel 2 and channel 3, in which case all STAs can receive and configure their NAV correctly.

In the following, all figures describing the MAC scheme refer to entities in the exemplary BSS of FIG. 2A, AP 204 and STA1 to STA4 2021 _{. . . 4} communication is channel 218 _{. . . 4} is done, the subscript indicates the sending entity. As explained above, for purposes of explanation, channel 218 _{1. . .} Each of ₄ is 1 MHz wide and it is assumed that channel 218 ₁ is the primary channel. Further, short frame intervals (SIFS) are used as exemplary frame intervals, but any other type of frame interval (IFS) may be used, including reduced IFS (RIFS) and arbitration IFS (AIFS). .

Examples of AP and STA behavior using DL MU-PCA with control frames transmitted over the entire bandwidth and over only the primary channel are shown in FIGS. 6 and 7, respectively. FIG. 6 shows an example MAC scheme 600 for enabling DL MU-PCA using control frames over the entire available bandwidth. In the example of FIG. 6, after an AP transmission 204 _AP of data packets to STA 2 that can support transmission / reception over the entire available bandwidth, and an ACK transmission 206 _{STA 2} back to the AP, the AP A free channel determination (CCA) can be performed in all available bandwidths.

After gaining access to all available channels, the AP performs all channel 218 _1. for either of the following functions: _{. . 4} can send G-RTS 606 _APs with channel assignments, and its function informs the group of STAs participating in DL MU-PCA about the channels they can switch to receive DL packets from APs At least until all acknowledgments for all DL MU-PCA packets are returned by the STA, configure all channels, NAVs for all STAs operating over these channels, potentially Securing them by using them as their own primary channel. Channel 218 _{1. . . If} one of the four is already occupied by some other STA, the G-RTS 606 _AP cannot be transmitted over that channel, and the STA in the DL MU-PCA group Cannot be assigned.

STAs in the DL MU-PCA group can switch to the channel assigned to them, and can also switch to the correct mode of operation, for example, STA1 is assigned to channel 1 218 ₁ so that it is channel 1 218 ₁ STA3 is assigned to channel 2, 3 218 _2-3 , so it can switch to channel 2, 3 and operate using 2MHz mode, and STA4 Assigned to 4 218 ₄ so it can be switched to channel 4 and operates using 1 MHz mode.

Thus, the STA can transmit G-CTS (or simply CTS) 608 _STA1 , 608 _STA3 , 608 _STA4 , respectively. These G-CTSs can inform the AP that it is ready to receive DL packets and, at least until the acknowledgment for all DL MU-PCA packets is returned by the STA, Can be reserved by setting NAVs for all nodes that operate and potentially using them as their own primary channel. For example, the duration field of (G-) CTS may be set to be the value of Duration_G-RTS-SIFS_Time- (G-) CTS_Time, where Duration_G-RTS is included in the G-RTS packet. It is a duration setting, SIFS_Time is the duration of SIFS 610, and (G-) CTS_Time is the transmission time of the G-CTS packet.

If from each _{STA (G-) CTS608 STA1, 608} STA3, 608 receives the _STA4, AP is to each STA, through the assigned channel can send data packets _{612 AP.} Since data packets can be different in length and can be transmitted using different MCSs, so that the entire BSS can be kept synchronized for operation within the BSS, depending on the timing of the primary channel. The longest packet may be selected to be transmitted on the primary channel 218 ₁ . All of the channels 218 _{1. . . A} padding 614 _AP may be transmitted by the AP over any channel to create (temporally) equal length data packets so that the DL transmission on ₄ ends at the same time. When the STA receives each data packet, the STA can send ACK packets 616 _STA1 , 616 _STA3 , and 616 _STA4 to the AP, respectively, in order to notify successful reception.

For STAs monitoring channels, if they receive a G-RTS from the AP that is not addressed to them, they wait for the duration and if no transmission from the AP is detected, they cancel the NAV. For example, (G-) CTS_Time + 2 * SIFS_Time + Y * A_Slot_Time + aPHY-RX-START-Delay, where (G-) CTS_Time is the duration of (G-) CTS packet 608 _STAX Time, SIFS_Time is the duration of SIFS 610, A_Slot_Time is the duration of the slot, aPHY-RX-START-Delay can be a delay in the PHY layer with respect to the start of reception, and Y is Configurable parameters It can be over data.

  The MAC DL MU-PCA shown in FIG. 6 indicates that STAs participating in the DL MU-PCA can switch not only between channels but also between transmission mode and reception mode within the SIFS interval. Assumes. However, if the STA cannot switch channels within the SIFS interval, the initial control packet exchange must be performed over the primary channel, as shown in FIG.

  FIG. 7 shows an example MAC scheme 700 for a single DL MU-PCA using G-RTS and G-CTS over the primary channel. The AP can perform CCA over all available channels. After gaining access to all channels, the AP can send a G-RTS 702 with channel assignments over all channels. The G-RTS 702 transmission sets all channels, NAVs for all nodes operating over these channels, at least until an acknowledgment for all DL MU-PCA packets is returned by the STA, Potentially, in order to reserve by using them as their own primary channel, and to groups of STAs participating in DL MU-PCA, they are SIFS between each STA's (G-) CTS. Not only about the order in which (G-) CTS should be sent over the primary channel with interval 710, but can also be used to inform about the channel that the STA should switch to receive DL packets from the AP. In order to provide the STA with sufficient time to switch channels, the STA assigned to receive over the primary channel has transmitted the CTS (or G-CTS) in the DL MU-PCA group last time. May be specified by the AP to be a STA.

Thereafter, the STA sequentially _passes (G-) CTS 704 _STA4 , 706 _STA3 , and 708 _STA1 according to the order assigned by the AP with a SIFS interval between each (G-) CTS via the primary channel. Can be sent. (G-) CTS 704 _STA4 , 706 _STA3 , and 708 _STA1 notify AP that it is ready to switch channels to receive DL packets, and at least for all DL MU-PCA packets Until the acknowledgment is returned by the STA, channels are reserved by setting NAVs for all nodes operating through these channels and potentially using them as their own primary channel Can help to keep. For example, the duration field of the nth (G-) CTS may be set to be Duration_G-RTS-Y × SIFS_Time-Y × (G-) CTS_Time, and Duration_G-RTS is included in the G-RTS packet. It is a duration setting included, SIFS_Time is the duration of SIFS, and (G-) CTS_Time is the transmission time of the (G-) CTS packet.

The first STA assigned to transmit within the MU-PCA group (STA4 in this example) can transmit a (G-) CTS after the SIFS time has elapsed after the first G-RTS frame. _Upon receiving (G-) CTS ₆₀₄ STA4 from STA4, which is the first STA, the AP requests the next STA (in this example) via the primary channel to request (G-) CTS from the second STA. STA3) can send another G-RTS (or another control frame such as G-Poll), for example, and the second STA can respond with (G-) CTS, after which the process This can be repeated until all STAs in the MU-PCA group transmit (G-) CTS frames. The duration fields in the G-RTS frame and (G-) CTS frame may be adjusted accordingly with the duration of the additional SIFS and G-RTS frames.

STAs in the DL MU-PCA group can switch to the channel assigned to them and can switch to the correct mode of operation. For example, STA1 is assigned to channel 1 218 ₁ , so it remains in channel 1 218 ₁ and can operate using the 1 MHz mode, and STA3 is assigned to channels 2, 3 218 _2-3 , so that Switching to channel 2 and channel 3 can operate using 2 MHz mode and STA4 is assigned to channel 4 218 ₄ so it can be switched to channel 4 and operate using 1 MHz mode.

Upon receiving (G-) CTS 704 _STA4 , 706 _STA3 , and 708 _STA1 , the AP can transmit data packets 712 _AP to the respective STAs through channels respectively assigned thereto. Since the data packet 712 _AP can be different in length and can be transmitted using different MCSs, the entire BSS can be kept synchronized for operation within the BSS depending on the timing of the primary channel. In addition, the longest packet may be selected to be transmitted over the primary channel. Padding can be used on all channels 218 _1-4 to create (temporally) equal length data packets so that the DL transmission ends at the same time. If one G-CTS is not received, the AP can choose not to transmit the DL packet for the corresponding STA over the assigned channel, or can choose to continue the transmission normally. When the STA receives each data packet, the STA sends ACK packets 716 _STA1 , 716 _STA3 , 716 _STA4 to the AP to notify the reception.

  For STAs monitoring channels, if they receive a G-RTS from the AP that is not addressed to them, they wait for the time period and if they do not detect transmission from the AP, they cancel the NAV. it can. For example, the time period may be equal to N * G-CTS_Time + (N + 1) * SIFS_Time + Y * A_Slot_Time + aPHY-RX-START-Delay, where N is the STA's included in the channel assignment of the G-RTS packet G-CTS_Time is the duration of the G-CTS packet, SIFS_Time is the duration of SIFS, A_Slot_Time is the duration of the slot, and aPHY-RX-START-Delay is the received It can be a delay in the PHY layer with respect to start, and Y can be a configurable parameter based on the WLAN system.

  FIG. 8 may be based on MPM, G-RTS, and to enable DL MU-PCA using control frames over the entire available bandwidth, and may comply with existing WiFi standards and drafts. Illustrated is an exemplary MAC scheme 800 that also enables MU-PCA for WiFi STAs, which may not be able to interpret G-CTS frames.

In the example of FIG _{. . .} AP transmission 802 _AP of data packet to STA2 capable of supporting transmission / reception over the entire _four 802 _AP can be acknowledged by STA2's ACK 804 _STA2 . The AP can send MPM frame _{806 AP,} MPM frame _{806 the AP,} it has a channel allocation for each STA in the MU-PCA group, DL MU-PCA (or DL SU-PCA) transmission announcement A selection may be included to indicate that In one example, the AP has all available bandwidth 218 _{1. . .} CCA can be performed on ₄ and all channels 218 _{1. . . 4} can send MPM806 _AP . The MPM frame 806 _AP is responsible for all channels 218 ₁ for the entire MU-PCA session _{. . . 4} can include information for setting the NAV on the MAC header. In another example, the MPM may not include NAV configuration information, and the AP may have a sufficiently short IFS 810 (eg, short IFS (SIFS)) to allow the AP to maintain access to the medium. Or all channels 218 using point IFS (PIFS)) _{. . . 4} on the media to be able to access, AP has all of the channels 218 _{1. . . 4} by sending a RTS frame _{808 AP} (or G-RTS frame) on, to be able to start the DL MU-PCA session.

In one example, AP performs CCA only on the primary channel 218 _1, can transmit the MPM frame _{806 AP} on the primary channel 218 _1. The MPM frame 806 _AP can announce a DL MU-PCA (or DL SU-PCA) session, after which the AP can all channel 218 _{1. . .} CCA can be performed on ₄ , and all channels 218 _{1. . . 4} has access on all channels 218 _{1. . . 4} can send an RTS frame 808 _AP (or G-RTS frame) to initiate a DL MU-PCA session.

All of the available channels 218 _{1. . .} After gaining access to ₄ , the _AP can send an RTS (or G-RTS) frame 808 _AP , which switches to the group of STAs participating in the DL MU-PCA to the channel to which they are assigned, It can be notified that DL packets can be received from the AP, and it will be able to notify all channels 218 ₁ at least until an acknowledgment for all DL MU-PCA packets is returned by the STA _{. . . 4} can be reserved by setting NAVs for all nodes operating over these channels and potentially using them as their own primary channel. If one of the channels is already occupied by some other STA, the RTS or G-RTS cannot be transmitted over that channel, and the STAs in the DL MU-PCA group Cannot be assigned.

  For WiFi STAs that may not be able to interpret MPM or G-RTS frames, the AP can either be on the primary channel or any set of continuous or non-consecutive channels including the primary channel on which the legacy WiFi STA can operate. Above, these STAs can be assigned. If a legacy WiFi STA is included in the MU-PCA session, the AP can send an RTS over all channels after first sending MPM frames to all (other) STAs, or at least a legacy WiFi device RTS can be transmitted through a channel to which is assigned.

In the example, if STA1 is 802.11n and the primary channel is channel 1, it can operate on both channel 1 and channel 2, 40 MHz bandwidth. The AP can allocate STA1 on channels 1 and 2 for 40 MHz operation. The AP can assign other STAs on channels 3 and 4 that can interpret MPM or G-RTS. The AP can then initiate an MU-PCA session by sending an RTS frame 808 _AP on channels 1, 2 or on all channels 1-4. In another example, if STA1 is 802.11acSTA, the primary channel is channel 1 with 80 MHz bandwidth, and STA1 enables 80 + 80 discontinuous operation, then the AP uses 80 + 80 discontinuous operation, STA1 can be assigned on channels 1,3. The AP can then allocate other STAs on channels 3 and 4 that can interpret MPM or G-RTS. The AP can then initiate an MU-PCA session by sending an RTS frame on channels 1, 3 or on all channels 1-4.

  STAs in the DL MU-PCA group can switch to the channel assigned to them and switch to the correct mode of operation. In one example, STA1 can be assigned to channel 1, so it can switch to channel 1 and operate using the 1 MHz mode, and STA3 can be assigned to channels 2, 3, so it can be assigned to channel 2, Can switch to 3 and operate using 2 MHz mode, and STA4 can be assigned to channel 4, so it can switch to channel 4 and operate using 1 MHz mode.

Referring back to the example of FIG. 8, STAs (STA1, STA3, STA4) can then send CTS (or G-CTS) 809 _STA1 , 809 _STA3 , 809 _STA4 via their assigned channels, Thereby, they can notify the AP that they are ready to receive DL packets and, at least until the acknowledgment for all DL MU-PCA packets is returned by the STA, the channels are routed through these channels. NAVs for all working nodes can be set up and potentially reserved by using them as their own primary channel. For example, the duration field of G-CTS may be set to be Duration_G-RTS-SIFS_Time-G-CTS_Time, where Duration_G-RTS is included in the RTS (or G-RTS) packet 808 _AP . It is a duration setting, SIFS_Time is the duration of IFS 810, and G-CTS_Time is the transmission time of the G-CTS packet. The STA can transmit a CTS frame when receiving an RTS from the AP, and can transmit a G-CTS when receiving a G-RTS from the AP.

_Upon receiving the CTS (or G-CTS) 809 _STA1 , 809 _STA3 , 809 _STA4 , the AP can transmit the data packet 812 _AP to each STA (STA1, STA3, STA4) via a channel assigned to each STA. . Data packet 812 _AP may be different in length (eg, data packet 812 _AP on channel 1 is longer than data packet 812 _AP on other channels) and may be transmitted using a different MCS. , the entire BSS is, depending on the timing of the primary channel 218 _1, so as to be able to maintain the synchronization operation of the BSS, the longest packet may be selected to be transmitted on the primary channel 218 _1. All of the channels 218 _{1. . .} As DL transmission on the ends at the same time _4, in order to create a data packet temporally equal length, the padding 814 _AP, all the channels 218 _{1. . . 4} can be used. STA (STA1, STA3, STA4) receives the respective data packet, to inform the reception, through the channel assigned to each, can be sent an ACK packet _{816 STA1, 816 STA3, 816 STA4} .

  For STAs that are monitoring channels, if they receive MPM, RTS, or G-RTS not addressed to them from the AP, they can wait for T-handshake + Y × A_Slot_Time + aPHY-RX-START-Delay, If no transmission is detected, they can cancel the NAV, where T-Handshake determines the duration of frames such as MPM, RTS, G-RTS, CTS, G-CTS, and multiple SIFS intervals. Including time for transmitting all packets to start MU-PCA transmission, A_Slot_Time is the duration of the slot, and aPHY-RX-START-Delay is the delay in the PHY layer for the start of reception And Y is It may be defined to suit the constant WLAN systems.

In addition to the examples described above in FIGS. 6-8, the DL MU-PCA data frame acknowledgment may also be implemented as a block ACK (BA). FIG. 9 shows an example MAC scheme 900 for enabling DL MU-PCA using control frames and BAs. In the example of FIG. 9, the AP can transmit data 904 _AP to the STAs (STA1, STA3, STA4) during the DL MU-PCA session 902 (the padding 906 _AP can be used if necessary). When the DL MU-PCA session 902 is terminated, the AP immediately or with some delay IFS 910 all channels 218 _{1. . . 4} can transmit a BAR frame 908 _AP . Upon receiving the BAR frame 908 _AP , the STA (STA1, STA3, STA4) can use the BA912 _STA1 , 912 _STA3 , 912 _STA4 to return an acknowledgment for the DL MU-PCA data frame 904 _AP received from the _AP . In another example, when the DL MU-PCA session ends, the STA can use the BA to return an acknowledgment for the DL MU-PCA data frame received from the AP. In another example, when a DL MU-PCA session ends, the AP can send a BAR frame over the primary channel immediately or with some delay IFS. A STA ranked as the first STA in the MU-PCA group can send a BA to the AP to return an acknowledgment for the DL MU-PCA frame received from the AP, and the AP can transmit the DL MU-PCA group. When a BA is received from the first STA in the block, a block ACK request frame (BAR) can be transmitted to the second STA in the MU-PCA group, and then the second STA can reply using the BA. This process can continue until all STAs in the MU-PCA group send the BA to the AP to return an acknowledgment for the DL MU-PCA frame received from the AP.

  A single UL MU-PCA can exchange packets such as uplink request (ULR), group poll (G-Poll), group ACK (G-ACK), and G-CTS (described below). It may be supported by a MAC scheme such as the examples shown in FIGS. To provide a detailed description of the three MAC schemes, the format of control frames such as ULR, G-Poll, G-ACK, and transmission of control frames are first described. The exemplary frames shown in FIGS. 10 and 11 do not show all possible fields that can be included in the frame. For example, the MAC header and frame body may include other fields not shown. Further, the fields can appear in any order and need not be in the order shown. For example, the type, subtype, and DA fields may not appear in the MAC header in the order shown.

  FIG. 10 shows an exemplary frame format of an uplink request frame (ULR) 1000. The ULR 1000 can include a MAC header 1002, a frame body 1004, and an FCS 1006. Type field 1014 and subtype field 1016 in MAC header 1002 may indicate that the frame is of type ULR (other fields 1018 may also be included in MAC header 1002). For example, the bits of type field 1014 and subtype field 1016 may be set according to Table 3.

  The frame body 1004 of the ULR 1000 uses the UL MU-PCA to identify APs such as, for example, the maximum allowable delay 1008, data size 1010, MCS 1012 used for transmission, and other information 1020 such as QoS priority, among others. Data specifications and uplink details may be included. In an example, data size 1010 and MCS 1012 may be combined into one field that represents the duration or transmission opportunity (TXOP) duration that the STA is requesting. The ULR 1000 may be implemented as any type of frame, such as an action frame, a no action ACK frame, or any other type of management or control frame, or as an IE, field, and subfield of a management and control frame.

  FIG. 11 shows an exemplary frame format of a group polling (G-Poll) frame 1100. The G-Poll frame 1100 can include a MAC header 1102, a frame body 1104, and an FCS 1106. Type field 1114 and subtype field 1116 may indicate that G-Poll frame 1100 is of type G-Poll. For example, the type field 1114 and the subtype field 1116 may be set according to Table 4.

  The DA field 1118 in the MAC header 1102 may be set to be a multicast MAC address representing a group of STAs if a MU-PCA group is formed and can be identified by the multicast MAC address. In another example, the DA field 1118 can be set to be a broadcast address, and the polled STAs can be identified in the frame body 1104 or by the group ID in the PLCP header (not shown). The G-Poll frame 1100 may also be transmitted to the unicast MAC address of the target STA.

The MAP field 1108 can be present in the frame body or in the MAC header 1102 or PLCP header (not shown) and can indicate how many STAs are being polled and other information contained in the frame body. STA of STA ID1110 _{1. . . N} can be, for example, an association ID (AID), a MAC address, or other form of ID that the AP and STA can establish in advance. If G-Poll is sent to a group of pre-established STAs, the STA ID may be omitted. The information 1112 included in the frame body 1104 can be, for example, a channel assigned to the STA on which the STA should transmit ULR in response to receiving the G-Poll frame 1100. G-Poll frame 1100 may be implemented as any type of frame, such as an action frame, a frame without action ACK, or any type of management or control frame, or as an IE, field, and subfield of a management and control frame. .

  The frame format of the group ACK (G-ACK) may indicate that the type field 1114 and the subtype field 1116 indicate that the frame is a type G-ACK, and the information 1112 may be different or absent. Except for this, the frame format of the G-Poll frame 1100 shown in FIG. Alternatively, assuming that the G-ACK has the same frame format as the G-Poll frame 1100 of FIG. 11, the MAP field 1108 portion of the G-ACK indicates that it is G-ACK instead of G-Poll. Can show. The G-ACK frame body may include a field for each STA in the group of STAs having one or more bits for acknowledgment for receipt of one or more packets. Each field may also indicate a starting sequence number for each STA for which the G-ACK frame notifies an acknowledgment. G-ACK may be implemented as any type of frame, such as an action frame, a frame without action ACK, or any other type of management and control frame, or as an IE or field of a management and control frame. Transmission of control packets such as G-Poll, ULR, G-CTS, and G-ACK associated with a single UL MU-PCA may be transmitted in multiple modes, as described above with respect to transmission of MPM frames. You can follow the same rules.

FIG. 12 shows an exemplary MAC scheme 1200 that supports UL MU-PCA for data without strict delay bounds. STAs inform the AP that they have an uplink packet to send if they gain access to the channel, or if they are being polled, or if they are sending packets to the AP In order to do so, the ULR can be sent to the AP, or the ULR can be piggybacked on the preceding UL packet destined for the AP, such as delay, data size, MCS used, or time / TXOP required, among others. Packet specifications can also be included. In the example of FIG. 12, STA4, STA3, and STA1 transmit ULR1202 _STA4 , 1204 _STA3 , 1206 _STA1 to the AP in order on primary channel 218 ₁ .

The AP uses the (G-) ACK transmission 1208 _AP (ie, an ACK or G-ACK frame) to indicate that it has received the ULR, either as a separate frame or as a piggyback portion of the transmitted packet. Can be notified. If the UL MU-PCA is scheduled to start immediately after the AP receives the ULR, the AP may not send a (G-) ACK. If the delay limit specified in the ULR frame elapses but there is no G-ACK or other piggyback type G-ACK received from the AP, the STA can assume that the ULR transmission failed. , It piggybacks another ULR independently or into another packet (eg, as an aggregate MAC protocol data unit (A-MPDU) or aggregate service protocol data unit (A-MSDU)), You can choose to send. It can choose to send the data packet directly to the AP.

In the example of FIG. 12, after acquiring an available channel, the AP can send a G-CTS 1212 _AP with channel assignment to a STA participating in the UL MU-PCA, which can do one of the following: That is, STAs participating in the UL MU-PCA are notified of the channels they are assigned to transmit UL packets, align the start of all UL transmissions from the STA, and / or all UL data Reserve media on all available channels by setting the G-CTS duration field, and thus the NAV for all monitoring STAs on these channels, until the ACK by the AP for the packet is finished You can do either. The duration field of the G-CTS 1212 _AP may be set to be 2 × SIFS_Time + Max_Data_Duration + ACK_Duration, for example, where SIFS_Time may be the duration of the SIFS 1210 interval, where ACK_Duration is the duration of the ACK frame 1216 _AP . Max_Data_Duration is all available channels 218 _{1. . . 4} may be the transmission of the longest data packet 1214 _STA1 in time, using the data size field and MCS field included in each ULR frame 1202 _STA4 , 1204 _STA3 , 1206 _STA1 . Can be calculated. The AP can also allocate the longest UL data packet transmitted (in time) on the primary channel 218 ₁ .

STA in UL MU-PCA group (STA1, STA3, STA4) via an assigned channel (e.g., STA1 is on channel 218 _1, STA3 are on channel _{218 2 to 3,} STA4 the channel 218 ₄ Above), uplink packets 1214 _STA1 , 1214 _STA3 , 1214 _STA4 can be sent to the AP, respectively.

The AP can wait for a further SIFS 1210 after the longest UL data packet ends, and can send an ACK 1216 _AP (or BA) to notify receipt of the UL packet. Alternatively, the AP has bandwidth 218 _{1. . .} Instead of doing it one by _one on the whole ₄ or on the primary channel 218 ₁ , a group ACK for all UL packets, which are ACKs encoded together, can be sent.

FIG. 13 shows an example MAC scheme 1300 that supports UL MU-PCA for data with tight delay bounds. This type of UL MU-PCA may be used, for example, for high priority STAs where the AP may periodically poll the STAs for UL packets. All of the available bandwidth 218 _{1. . .} After acquiring the channel on ₄ , the AP can use the available channel 218 _{1. . . 4} can send a G-Poll frame 1302 _AP , which polls the STA for the presence of uplink packets and informs the STA on which it can respond using ULR packets on it And / or by setting the NAV for the STA that monitors the channel and thus the duration field may help to reserve the channel. UL STA in MU-PCA group (STA1, STA3, STA4) is assigned to each channel (STA1 ₂₁₈ 1, STA3 ₂₁₈ 2,3, STA4 ₂₁₈ 4), and to switch to the appropriate transmission mode In response to the G-Poll frame 1302 _AP using the ULR packet transmission 1304 _STA1 , 1304 _STA3 , 1304 _STA4 via the respective channels, the AP can be notified of the UL packets that they may have.

The AP can send a G-CTS 1306 _AP with channel assignments to STAs participating in the UL MU-PCA, which does one of the following: all UL transmissions from the STA 1308 _STA1 , 1308 _STA3 , 1308 _{Align STA4} start, ACK frame 1312 by _AP for all UL data packets 1308 _STA1 , 1308 _STA3 , 1308 _STA4 until the G-CTS 1306 _AP duration field is terminated, thus on these channels by setting the NAV of all monitoring STA (STA1, STA3, STA4) , all available channels 218 _{1. . .} Any of securing media on ₄ can be performed. The duration field of the G-CTS 1306 _AP may be set to be 2 × SIFS_Time + Max_Data_Duration + ACK_Duration, where SIFS_Time may be the duration of the SIFS interval 1310, where ACK_Duration is the duration of the ACK frame 1312 _AP. Max_Data_Duration is all available channels 218 _{1. . . 4} may be the transmission of the longest data packet in time (1308 _{STA1 in} this example), which is the data size included in each ULR frame 1304 _STA1 , 1304 _STA3 , 1304 _STA4 Fields and MCS fields can be used to calculate. The AP can also allocate the longest temporal UL data packet (1308 _{STA1 in} this example) transmitted on the primary channel 218 ₁ . All STAs (STA1, STA3, STA4) in the UL MU-PCA group can transmit uplink packets 1308 _STA1 , 1308 _STA3 , 1308 _STA4 to the AP via their assigned channels. The AP can wait for a further SIFS interval 1310 after the longest UL data packet ends, and to acknowledge receipt of UL packets 1308 _STA1 , 1308 _STA3 , 1308 _STA4 , ACK 1312 _AP (or BA) can be transmitted.

For STAs monitoring channels (eg, STA2), if they receive a G-Poll frame 1302 _AP not addressed to them from the _AP , they may wait for ULR_Time + 2 × SIFS_Time + Y × A_Slot_Time + aPHY-RX-START-Delay. If transmission from the AP is not detected, they can cancel the NAV, where ULR_Time is the duration of ULR packet 1304 _STA4 , SIFS_Time is the duration of SIFS 1310, and A_Slot_Time is the slot's duration The duration, aPHY-RX-START-Delay may be a delay in the PHY layer with respect to the start of reception, and Y is a configurable parameter.

As an alternative to FIG. 13, FIG. 14 shows an exemplary MAC scheme 1400 that supports UL MU-PCA for data in which ULR packets are sent in order. Similar to FIG. 13, the AP can transmit the G-Poll 1402 _AP to STAs in the MU-PCA group. ULR packets 1404 _STA4 , 1406 _STA3 , 1408 _STA1 from STAs in the UL MU-PCA group may be sent in order on primary channel 218 ₁ for STAs that cannot quickly switch channels and operating modes. The G-Poll 1402 _AP transmitted by the AP transmits the ULR to the STA assigned to transmit via the primary channel (STA1 in this example), ULR transmission 1404 _STA4 , 1406 _STA3 , 1408 at the end of the _STA1 order. The frame can be sent to allow other STAs in the UL MU-PCA group sufficient time to switch channels and operating modes. Similar to FIG. 13, the AP has all channels 218 _{1. . . 4} can send a G-CTS 1412 _AP, which can send an ACK 1416 _AP and return an acknowledgment regarding the reception of data transmission 1414 _STA1 , 1414 _STA3 , 1414 _STA4 by STA (STA1, STA3, STA4) .

  In another example, the first STA in the MU-PCA group can transmit a ULR after SIFS time from the first G-Poll frame, and upon receiving the ULR from the first STA, the AP Via the STA can send another G-Poll (or another control frame, eg, PS-Poll) to the second STA, requesting the ULR from the second STA, And the process can be repeated until all STAs in the MU-PCA group have transmitted ULR frames. A STA polled by an AP may not have a UL packet to send. In this case, the AP can assign a channel to the STA that previously notified the AP that it has a UL packet.

In another example, all available bandwidths 218 _{1. . .} After acquiring the channel on ₄ , the AP can use the available channel 218 _{1. . . 4} can send a G-Poll frame, which polls the STA for the presence of uplink packets and / or the assigned channel on which it can respond with UL packets. Can be helpful to inform. STAs in the MU-PCA group can switch to the assigned channel after an IFS interval, such as SIFS, and immediately begin sending UL packets to the AP.

FIG. 15 shows an exemplary MAC scheme 1500 that supports UL MU-PCA for data with mixed delay requirements. A STA that does not belong to the UL MU-PCA group (eg, STA2) can notify the AP that it has a UL packet by transmitting the ULR1502 _STA2 to the AP. The indication and specification of the UL packet can also be piggybacked on the preceding packet sent to the AP by the STA (STA2). The AP can inform the _STA2 of the reception of the ULR1502 _STA2 by transmitting the (G-) ACK frame 1504 _AP . (G-) ACK frame 1504 The _AP may be an acknowledgment regarding reception to the group of STAs that have informed that it has a UL packet addressed to the AP. The (G-) ACK may be piggybacked on another DL packet or broadcast / multicast packet. The AP sends a UL packet to be transmitted by sending a G-Poll frame 1506 _AP with a channel assigned to each STA on which they can send ULR packets 1508 _STA1 , 1508 _STA3 , 1508 _STA4 to the AP. Can be polled for a group of MU-PCA STAs (STA1, STA3, STA4). The STA, for example, the STA 4 may indicate that there is no UL packet to be transmitted.

The AP is part of the UL MU-PCA group and can transmit the G-CTS 1512 _AP with channel assignment to STAs (in this example, STA1 and STA3) that have UL packets to transmit. It can also send a G-CTS 1512 _AP that contains information for STA2 that previously signaled that it has a UL packet to send, which does one of the following: STA2 assigned channel 218 ₄ and command to switch to operating mode, align start of all UL transmissions from _STA , ACK 1516 by _AP for all UL data packets 1514 _STA1 , 1514 _STA3 , 1514 _STA2 until G- By setting the CTS 1512 _AP duration field, and thus the NAV for all monitoring STAs on these channels, all available channels 218 _{1. . .} Any of securing media on ₄ can be performed. The duration field of the G-CTS 1512 _AP may be set to be 2 × SIFS_Time + Max_Data_Duration + ACK_Duration, where SIFS_Time is the duration of the SIFS interval 1510, ACK_Duration is the duration of the ACK frame 1516 _AP , and Max_Data_Data_Data All available channels 218 _{1. . . 4} is the transmission of the longest data packet transmitted in time (1514 _{STA1 in} this example), which is included in each ULR frame 1508 _STA1 , 1508 _STA3 , 1508 _STA4 and / or ULR 1502 It can be calculated using the data size field and the MCS field from _STA2 . The AP can also allocate the longest time UL data packet (1514 _STA1 ) transmitted on the primary channel 218 ₁ .

All STAs (STA1, STA3) and STA2 in the UL MU-PCA group having data to transmit transmit uplink packets 1514 _STA1 , 1514 _STA3 , 1514 _STA2 to the AP via their assigned channels. it can. The AP can wait for a further SIFS interval 1510 after the longest UL data packet (1514 _STA1 ) expires, to notify receipt of UL data packets 1514 _STA1 , 1514 _STA3 , 1514 _STA2. ACK1516 _AP can be transmitted.

  In addition to the acknowledgment methods described above, UL MU-PCA frame acknowledgments can be similarly implemented using BAs. The AP can return an acknowledgment for the UL MU-PCA, eg, at the end of the UL MU-PCA session, and the AP can acknowledge the UL MU-PCA frame received via the individually assigned channel from the STA. BA can be used to return a response. In another example, at the end of the UL MU-PCA session, the STA can send a BAR frame over the assigned channel immediately or with some IFS delay. When an AP receives a BAR from a STA, the AP can use the BA to return an acknowledgment for the UL MU-PCA data frame received from the STA over the channel assigned to that STA. In another example, at the end of the UL MU-PCA session, a STA ranked as the first STA in the MU-PCA group can send the BAR to the AP immediately or with some IFS delay. The AP can send a BA to return an acknowledgment for the UL MU-PCA frame received from the STA. When the first STA receives the BA from the AP, the second STA in the MU-PCA frame can send the BAR to the AP, and then the AP can respond with the BA. This process can continue until the AP sends a BA to all STAs in the UL MU-PCA group. In another example, the AP can choose to send the BA to all STAs in the UL MU-PCA group without an explicit BAR from the STA. In another example, at the end of the UL MU-PCA session, the AP can send an ACK or BA or group ACK over the primary channel or all channels to all STAs in the UL MU-PCA group. A frame may be defined to return an acknowledgment for one or more frames to a group of STAs.

  UL and DL MU-PCA may be further combined to significantly reduce signaling overhead in group configuration / setup. A MAC scheme that supports combined UL / DL MU-PCA is shown in FIGS. 16-20 illustrate specific MAC schemes as examples, each feature or element includes or includes other features and elements alone, without other features and elements of the described MAC scheme Note that not various combinations can be used.

FIG. 16 shows an example of a MAC scheme 1600 that supports combined DL and UL MU-PCA. Prior to initiating this scheme, the AP may do one of the following: UL MU-PCA, which may be piggybacked on a DL MU-PCA packet and / or a G-ACK that terminates the DL MU-PCA packet Any of the signaling to request transmission can be transmitted. All of the available channels 218 _{1. . .} After you gain access to the _4, AP, all of the channels 218 _{1. . . 4} can send a G-RTS 1602 _AP with channel assignment, which can do any of the following: to a group of STAs participating in DL MU-PCA (STA1, STA3, STA4) Notifying the channel to be switched to receive DL packets from the AP, all channels 218 _1. Until an acknowledgment for all DL MU-PCA packets is returned by the STA _{. . . 4} to set up NAV for all nodes operating through these channels and potentially reserve them by using them as their own primary channel Can help. If one of the channels is already occupied by some other STA, the G-RTS cannot be transmitted over that channel and the STA in the DL MU-PCA group is assigned to that channel. It cannot be done. Alternatively, the MPM can be sent instead of the G-RTS 1602 _AP .

Following the G-RTS 1602 _AP , STAs in the DL MU-PCA group can switch to the channels assigned to them and switch to the correct mode of operation. STAs (STA1, STA3, STA4) can then send (G-) CTS1604 _STA1 , 1604 _STA3 , 1604 _STA4 , which is ready to do any of the following, ie to receive DL packets: To configure the channels, NAVs for all nodes operating over these channels, and at least until the acknowledgment for all DL MU-PCA packets is returned by the STA Can either be reserved by using them as their own primary channel. (G-) CTS 1604 _STA1 , 1604 _STA3 , 1604 _Upon receiving _STA4 , the _AP is given (possibly padding 1608 _AP ) to each STA (STA1, STA3, STA4) via the channel assigned to each STA (STA1, STA3, STA4). Data packet 1606 _AP can be transmitted. Since the data packet 1606 _AP may be different in length and may be transmitted using different MCSs, the entire BSS may remain synchronized for operation within the BSS depending on the timing of the primary channel 218 _1. As possible, the longest packet may be selected to be transmitted on the primary channel 218 ₁ . In order to create a data packet 1606 _AP of equal length in time so that the DL transmission ends at the same time, the padding 1608 _AP has all channels 218 _{1. . . 4} can be used.

When the STA (STA1, STA3, STA4) receives each data packet 1606 _AP and successfully decodes the data, an ACK, BA, or G-ACK packet 1612 _STA1 , 1612 _STA3 , 1612 _STA4 can be transmitted. Acknowledgments for DL MU-PCA packets may not be required until the MU-PCA session is terminated or until the AP explicitly requests an ACK or BA using a BAR frame. If the STA (STA1, STA3, STA4) has a UL packet to be transmitted to the AP, the STA (STA1, STA3, STA4) sets the more fragment bits in the MAC header of the ACK, BA, or G-ACK frame (1612 _STA1 , 1612 _STA3 , or 1612 _STA4 ). By setting to be “1”, the AP can be notified or some other display method can be used.

The duration field of each G-ACK frame 1612 _STA1 , 1612 _STA3 , 1612 _STA4 may be set equal to 3 × SIFS_Time + Data_Duration + G-CTS_Time + ACK_Duration, where SIFS_Time may be the duration of SIFS interval 1610 , ACK_Duration can be the duration of (G-) ACK frame 1618 _STA1 , 1618 _STA3 , or 1618 _STA4 , and Data_Duration is the UL data packet length (eg, the length of packet 1616 _STA1 , 1616 _STA3 , or 1616 _STA4 ). is), and MC used by the DL data packet 1606 _AP for each STA The resulting calculated by using, G-CTS_Time may be the same as the _{G-CTS (1604 STA1, 1604} STA3 or _{1604 STA4,)} the duration of the preceding sent to the AP by the STA.

  In one example, an ACK, BA, or G-ACK frame indicates that the STA can start sending UL packets by conveying a reverse grant (RDG) for the STA in the DL MU-PCA data frame. Can be omitted, or can be delayed with some delay after DL MU-PCA transmission. This RDG indication may be implemented by setting the RDG / more PPDU indicator in the MAC header or by using other methods.

Referring to FIG. 16, an _AP may transmit a G-CTS 1614 _AP that may include a UL channel assignment that may differ from a DL channel assignment to a STA participating in the UL MU-PCA. G-CTS1614 _AP, because of any of the following, namely, to align the beginning of all UL transmission _{1616 STA1, 1616 STA3, 1616 STA4} from STA, for example, all UL data packets _{1616 STA1, 1616 STA3,} 1616 until According to AP for _STA4 (G-) ACK1618 _AP is finished, the duration field of the G-CTS, therefore, by setting the NAV of all monitoring STA on these channels, which all available channel 218 _{1. . . 4} can be used to reserve media. The duration field of the G-CTS 1614 _AP may be set to be 2 × SIFS_Time + Max_Data_Duration + ACK_Duration, where SIFS_Time is the duration of the SIFS interval 1610 and ACK_Duration is the duration of the (G-) ACK frame 1618 _AP Max_Data_Duration is the transmission of the longest data packet in time (1606 _AP on channel 218 _{1 in} this example) transmitted over all available channels, which is G-ACK It is obtained from the duration field of frame 1612 _STA1 , 1612 _STA3 , or 1612 _STA4 .

  In another example where the AP signals the RDG in a DL MU-PCA data frame, the AP can choose not to send a G-CTS. If the STA in the UL MU-PCA has a UL frame to transmit, it will start with a certain IFS delay when the DL MU-PCA frame ends over the assigned channel, possibly. UL MU-PCA transmission can be started.

Referring to FIG. 16, from the AP (G-) CTS1614 following the receipt of the _AP, UL MU-PCA STA in the group (STA1, STA3, STA4) are respectively assigned channels (STA1 channel 218 ₁ STA3 can transmit uplink packets 1616 _STA1 , 1616 _STA3 , 1616 _STA4 to the AP on channel 218 ₂ , ₃ and STA4 on channel 218 ₄ ). The AP can wait for a further SIFS interval 1610 after the longest UL data packet in this example (1616 _{STA1 in} this example) is finished, and receive the UL packets 1616 _STA1 , 1616 _STA3 , 1616 _STA4. In order to notify (STA1, STA3, STA4), a (G-) ACK frame 1618 _AP can be transmitted. In another example, ACKs that are encoded together are all channels 218 _{1. . . 4} or only on primary channel 218 ₁ may be transmitted. ACK is used for all channels 218 _{1. . . 4} or only on the primary channel 218 ₁ can also be implemented as a BA or multi-user ACK, or the AP can send the BA if the STA requests them using a BAR.

  FIG. 17 shows an exemplary flow diagram 1700 of a method for combined DL and UL MU-PCA performed by a STA in a BSS system where the STA is part of a MU-PCA group. At 1705, the STA indicates from the AP via the channel associated with the STA that the AP is ready to transmit data messages simultaneously via channels available to the STAs in the MU-PCA group. RTS can be received. At 1710, the STA sends a ready to send (CTS) indication to the AP via the channel associated with the STA that the STA is ready to receive via the channel associated with the STA. it can. The CTS can reserve a channel associated with the STA for the STA during the MU-PCA session. At 1715, the STA can receive a data message from the AP via a channel associated with the STA, and the data message is part of a group of multiple simultaneous data messages on the available channel.

  At 1720, the STA can send an acknowledgment (ACK) message (or G-ACK or BA) to the AP over the channel associated with the STA, and the ACK (or G-ACK or BA) is transmitted by the STA. More fragment bits can be included that are set to be “1” when having uplink data to be transmitted to the AP. If at 1725 the More Fragment bit is set to be 1, indicating the presence of UL data at the STA, then at 1730, the STA associates with the STA from the AP via the channel assigned to the STA. Receive ready to send (CTS) messages, indicating that the designated channel has been reserved for UL transmission of the STA and that the STA can send UL data over the channel associated with the STA . Any of the messages in FIG. 17 including RTS, CTS, and ACK may be group messages, eg, group RTS (G-RTS), group CTS (G-CTS), and group ACK (G-ACK). it can.

FIG. 18 shows an exemplary MAC scheme 1800 that supports combined UL and DL MU-PCA. Prior to this MAC scheme 1800, a group of STAs may be piggybacked on one of the following: UL MU-PCA packet to AP and G-ACK terminating UL MU-PCA packet, DL Any of the signaling for MU-PCA transmission can be transmitted. All of the available bandwidth 218 _{1. . .} After acquiring the channel on ₄ , the AP can use the available channel 218 _{1. . . 4} can send a G-Poll frame 1802 _AP , which polls the STA for any of the following: asks for the presence of an uplink packet, and responds to the STA with a ULR packet on it Either reserving the possible channels and / or reserving the channel by setting the duration field, and thus the NAV for the STA that monitors the channel, can be achieved. The STAs (STA1, STA3, STA4) in the UL MU-PCA group can switch to the assigned channel and the appropriate transmission mode, the assigned channel (STA1 is 218 ₁ , STA3 is 218 _{2, 3} , STA4 can notify the AP about the UL packets that they have in response to G-Poll using ULR packets 1804 _STA1 , 1804 _STA3 , 1804 _STA4 on 218 ₄ ).

The AP is responsible for each channel 218 _{. . . 4} can send a G-CTS 1806 _AP with channel assignment to STAs participating in UL MU-PCA, which can do any of the following: all UL transmissions 1808 _STA1 , 1808 _STA3 , 1808 from the STA _Align start of _STA4 , G-CTS 1806 _AP duration field until (G-) ACK frame 1812 _AP by AP returning acknowledgment to all UL data packets 1808 _STA1 , 1808 _STA3 , 1808 _STA4 And therefore all available channels 218 _1. by setting NAV for all monitoring STAs on these channels _{. . .} Any of securing media on ₄ can be achieved. The duration field of the G-CTS 1806 _AP may be set to be 2 × SIFS_Time + Max_Data_Duration + ACK_Duration, where SIFS_Time may be the duration of the SIFS interval 1810, where ACK_Duration is a (G−) ACK frame 1812 _AP. Max_Data_Duration is all available channels 218 _{1. . . 4} may be the transmission of the longest data packet (1808 _{STA1 in} this example) transmitted in time, which is the data size included in each ULR frame 1804 _STA1 , 1804 _STA3 , 1804 _STA4 Fields and MCS fields can be used to calculate. The AP can also allocate the longest temporal UL data packet (1808 _{STA1 in} this example) transmitted on the primary channel 218 ₁ .

All STA in UL MU-PCA group (STA1, STA3, STA4) the channel assigned to each (STA1 ₂₁₈ 1, STA3 ₂₁₈ 2,3, STA4 218 ₄₎ on the uplink packet 1808 _STA1 , 1808 _STA3 , 1808 _STA4 can be transmitted to the AP. The AP can wait for a further SIFS interval 1810 after the longest UL data packet ends, and if the AP can successfully decode the received data packet, it sends a G-ACK frame 1812AP. Te, UL packet _{1808 STA1, 1808 STA3, 1808} can inform the reception of _STA4. If one or more UL data packets are not decoded correctly, the AP cannot send a G-ACK packet over the corresponding channel. In the example, if the AP has a DL packet to be sent to a STA that did not correctly receive the UL packet, the AP can send a G-CTS addressed to itself. The (G-) CTS 1896 _AP duration field setting may be the same as the G-ACK duration field setting described below. The (G-) ACK 1812 _AP may be implemented as any type of frame, eg, an ACK, BA, or multi-user ACK frame. In an example, an acknowledgment for a UL MU-PCA packet may be omitted until the MU-PCA session ends or until the STA explicitly requests an ACK or BA using a BAR frame.

Referring to FIG. 18, if the AP has a DL packet to send to the STA, the more fragment bit in the MAC header of the G-ACK frame 1812 _AP can be set to “1”, or any other arbitrary A method can be used to provide an indication. The duration field of the G-ACK frame 1812 _AP may be set to be 2 × SIFS_Time + Data_Duration + ACK_Duration, where SIFS_Time is the duration of the SIFS interval 1810 and ACK_Duration is the (G-) ACK frame 1812 _AP 's duration. The duration, Data_Duration, is calculated by using the longest DL data packet in time (in this example, the data packet 1814 _AP on channel 218 ₁ ). In the example where the AP does not provide an ACK, the STA may include an RDG indicator in the UL MU-PCA frame to provide a reverse grant to the AP that should transmit the DL MU-PCA frame.

The AP can send a data packet 1814 _AP to each STA over the assigned channel, which can be done after the SIFS interval 1810 elapses. Since the data packet 1814 _AP may be different in length and may be transmitted using different MCSs, the entire BSS may be synchronized for operation within the BSS depending on the timing of the primary channel 218 _1. As can be done, the longest packet 1814 _AP may be selected to be transmitted on the primary channel 218 ₁ . In order to create a data packet of equal length in time so that the DL transmission ends at the same time, the padding 1816 _AP may select any channel 2181 _{. . . 4} can be used. When the STA receives each data packet 1814 _AP , the _STA can transmit ACK packets 1818 _STA1 , 1818 _STA3 , and 1818 _STA4 via the respective channels to notify the reception. ACKs 1818 _STA1 , 1818 _STA3 , 1818 _STA4 may be implemented as _BAs . In another example, an acknowledgment for a DL MU-PCA packet may be omitted until the MU-PCA session ends or until the AP explicitly requests an ACK or BA using a BAR frame.

FIG. 19 illustrates an example in which UL MU-PCA transmission is initiated by a ULR transmitted sequentially over the primary channel, and individual messages function as described above with respect to other exemplary MAC schemes. A MAC scheme 1900 is shown. Each STA (STA1, STA3, STA4) in the MU-PCA can sequentially transmit ULR frames 1902 _STA4 , 1904 _STA3 , 1906 _STA1 to the AP on the primary channel 218 ₁ , and the AP can transmit the primary channel via the primary channel, By sending a G-ACK 1908 _AP , an acknowledgment can be returned. The AP sends each channel 218 ₁ to STAs participating in the UL MU-PCA _{. . . 4} can transmit G-CTS 1912 _AP with channel assignment. STAs can transmit data 1914 _STA1 , 1914 _STA3 , 1914 _STA4 on their assigned channels (STA1 is 218 ₁ , STA3 is 218 _2,3 , STA4 is 218 ₄ ), and AP By transmitting the G-ACK 1916 _AP through the network, an acknowledgment for data that has been successfully received can be returned.

The AP can send a data packet 1918 _AP to each STA over the assigned channel, which can be done after the SIFS interval 1910 has elapsed. Since the data packet 1918 _AP may be different in length and may be transmitted using different MCSs, the entire BSS may be synchronized for operation within the BSS depending on the timing of the primary channel 218 _1. As can be done, the longest packet 1918 _AP may be selected to be transmitted on the primary channel 218 ₁ . In order to create a data packet of equal length in time so that the DL transmission ends at the same time, the padding 1920 _AP can use any channel 218 _{1. . . 4} can be used. STA can transmit when receiving the respective data packet 1918 _AP, in order to inform the reception, through the respective channels, ACK packet _{1922 STA1,} 1922 _STA3, the _{1922 STA4.}

FIG. 20 enables combined DL / UL MU-PCA using control frames over the entire available bandwidth and may comply with WiFi standards and drafts, but MPM, or G-RTS, An exemplary MAC scheme 2000 is also shown that also enables MU-PCA for legacy WiFi STAs that may not be able to interpret G-CTS or G-ACK frames. An AP can initiate a MU-PCA session by sending a MU-PCA management (MPM) frame 2002 _AP , which is an MPM frame that is sent to each STA (STA1, STA3, STA4) in the MU-PCA group. A selection may be included that indicates a combined DL / UL MU-PCA transmission announcement with a channel assignment for.

In the example, the AP has all available channels 218 _{1. . .} It performs a CCA on at _4, all of the channels 218 _{1. . . 4} can transmit MPM frame 2002 _AP . The MPM frame 2002AP may include information in the MAC header to set the NAV on all channels for the entire MU-PCA session. In an example, the MPM may not include NAV configuration information, instead the AP uses a sufficiently short IFS 2010 such as SIFS or PIFS to allow the AP to maintain access to the medium. All channels 218 _{1. . . 4} on the media to be able to access, AP has all of the channels 218 _{1. . . 4} (G-) RTS frame 2004 _AP frame is transmitted to allow DL / UL MU-PCA session to be initiated. In another example, AP may perform CCA only on the primary channel 218 _1, can transmit the MPM frame 2002 _AP on the primary channel 218 _1. The MPM frame 2002 _AP can announce the DL / UL MU-PCA session, after which the AP can all channel 218 _{1. . .} CCA can be performed on ₄ and all channels 218 _{1. . . 4} accesses all channels 218 _{1. . . 4} can send a (G-) RTS frame 2004 _AP to continue the DL / UL MU-PCA session.

Referring to FIG. 20, all available channels 218: _{1. . .} After gaining access to ₄ , the _AP can send an RTS (or G-RTS) frame 2004 _AP over all channels, which participates in one of the following: DL MU-PCA Notifying the group of STAs (STA1, STA3, STA4) that they can switch to the assigned channel and receive DL packets from the AP, acknowledgments for all DL / UL MU-PCA packets are returned by the STA until, all of the channels 218 _{1. . . 4} to set up NAV for all nodes operating through these channels and potentially secure them by using them as their own primary channel Can be helpful. If one of the channels is already occupied by some other STA, the (G-) RTS cannot be sent over that channel, and the STAs in the MU-PCA group Cannot be assigned.

For legacy WiFi STAs, which may not be able to interpret MPM or G-RTS frames, the AP may send these STAs to the primary channel 218 ₁ , or any primary channel on which the legacy WiFi STA can operate. Can be assigned to continuous or discontinuous channels. If a legacy WiFi STA is included in the MU-PCA session, the AP first sends an MPM frame 2002 _AP to all STAs and then all channels 218 _{1. . . 4} can transmit an RTS frame 2004 _AP , or at least an RTS frame 2004 _AP can be transmitted over a channel to which a legacy WiFi device is assigned. In the example, if STA1 is an 802.11n STA whose primary channel is channel 1 and can operate on a 40 MHz bandwidth in both channel 1 and channel 2, the AP will consequently cause STA1 to operate at 40 MHz. Can be assigned to channel 1 and channel 2. The AP can assign channel 3 and channel 4 with other STAs that can interpret MPM or G-RTS. The AP can send an RTS frame on channel 1 and channel 2 or over all channels to initiate a MU-PCA session. In another example, if STA1 is an 802.11ac STA where the primary channel is channel 1 (80 MHz) and STA1 is capable of 80 + 80 discontinuous operation, the AP uses 80 + 80 discontinuous operation. STA1 can be allocated on channel 1 and channel 3. The AP can then assign channel 2 and channel 4 with other STAs that can interpret MPM or G-RTS. The AP can then send an RTS frame on channel 1 and channel 3 or via all channels to initiate a MU-PCA session.

Referring to FIG. 20, STAs (STA1, STA3, STA4) in the MU-PCA group can switch to the channels assigned to them, and can switch to the correct operation mode. Assigned to 218 ₁ , so it can switch to channel 218 ₁ and can operate using 1 MHz mode, STA3 is assigned to channel 218 _2,3 , so it switches to channel 218 _2,3 , can operate using 2MHz mode, STA4 is assigned to the channel 218 _4, therefore, it is switched to the channel 218 _4, can operate using 1MHz mode.

The STA can then send (G-) CTS 2006 _STA1 , 2006 _STA3 , 2006 _STA4 , which informs the AP that it is ready to receive the DL packet 2008 _AP , either: At least until the acknowledgments for all DL / UL MU-PCA packets (2014 _STA1 , 2014 _STA3 , 2014 _STA4 ) are returned by the STA, the channels will have NAVs for all nodes operating over these channels. Either setting up and potentially reserving by using them as their own primary channel can be achieved. For example, the duration field of (G-) CTS2006 _STA1 , 2006 _STA3 , 2006 _STA4 may be set to be Duration_ (G-) RTS-SIFS_Time- (G-) CTS_Time, where Duration_ (G-) The RTS may be a duration setting included in the (G-) RTS frame 2004 _AP , SIFS_Time may be the duration of the SIFS interval 2010, and (G-) CTS_Time is (G-) CTS2006 _STA1, a _{2006 STA3, 2006 STA4} transmission time. In the example, each STA in the MU-PCA group, if it receives the RTS frame 2004 _AP from the AP, CTS frame _{2006 STA1, 2006 STA3, 2006 STA4} can send, G-RTS frame 2004 it from AP _{When the AP} is received, G-CTS 2006 _STA1 , 2006 _STA3 , and 2006 _STA4 can be transmitted.

_Upon receiving the CTS or G-CTS 2006 _STA1 , 2006 _STA3 , 2006 _STA4 , the AP can transmit a data packet 2008 _AP to each STA via the assigned channel. Since the data packet 2008 _AP may be different in length and may be transmitted using different MCSs, the entire BSS may be synchronized for operation within the BSS depending on the timing of the primary channel 218 _1. As possible, the longest packet may be selected to be transmitted on the primary channel 218 ₁ . Padding 2012 _AP can be used over any required channel to create data packets of equal length in time so that DL transmissions on all channels end at the same time. When the STA receives each data packet 2008 _AP and successfully decodes the data, the STA transmits an ACK (or BA or G-ACK) packet 2014 _STA1 via a channel assigned to each _AP to notify the successful reception. , 2014 _STA3 , 2014 _STA4 . In an example, an acknowledgment for a DL MU-PCA packet 2008 _AP may be omitted or delayed until the MU-PCA session ends or until the AP requests an ACK or BA using a BAR frame. .

When the STA has a UL packet to be transmitted to the AP, the STA can set the more fragment bit in the MAC header of the ACK (BA or G-ACK) frame 2014 _STA1 , 2014 _STA3 , 2014 _STA4 to be “1”; Or some other display method can be used. The duration field of (G-) ACK 2014 _STA1 , 2014 _STA3 , 2014 _STA4 may be set to be equal to 3 × SIFS_Time + Data_Duration + (G-) CTS_Time + (G-) ACK_Duration, where SIFS_Time is the SIFS interval 2010 ACK_Duration is the duration of ACK frames 2014 _STA1 , 2014 _STA3 , 2014 _STA4 , Data_Duration is the length of UL data packets (2018 _STA1 , 2018 _STA3 , 2018 _STA4 ), and DL data packet 2008 _AP The (G-) CTS_Time is calculated by the STA as AP _Can be of the same duration as the preceding (G-) CTS 2006 _STA1 , 2006 _STA3 , 2006 _STA4 .

  In examples where an ACK (or BA or G-ACK) frame is omitted or delayed, the AP transmits DL MU- by conveying a reverse grant (RDG) for the STA in the DL MU-PCA data frame. After the PCA transmission, it can be indicated that the STA can start transmission of the UL packet with some delay in some cases. Such RDG display may be implemented, for example, by setting an RDG / more PPDU indicator in the MAC header, or by any other display method.

The AP may include CTS or G-CTS frame 2106 _AP (G-CTS may include channel assignments that may be different from DL channel assignments, via channels assigned to each STA participating in UL MU-PCA. Can send). The CTS frame 2016 _AP aligns any of the _following: the start of all UL transmissions 2018 _STA1 , 2018 _STA3 , 2018 _{STA4 from} the _STA , the AP for all UL data packets 2018 _STA1 , 2018 _STA3 , 2018 _STA4 Until the ACK frame 2020 _AP by the end of the (G-) CTS frame 2016 _AP 's duration field, and therefore by setting the NAV for all monitoring STAs on these channels, all available channels 218 _{1. . . 4} can help to achieve any of securing media on. The duration field of the (G-) CTS frame 2016 _AP may be set to be 2 × SIFS_Time + Max_Data_Duration + (G−) ACK_Duration, where SIFS_Time is the duration of the SIFS interval 2010, and (G−) ACK_Duration Is the duration of the ACK frame 2020 _AP , and Max_Data_Duration is the transmission of the longest data packet 2018 _STA1 transmitted over all available channels, which is (G-) ACK It is obtained from the duration field of the frames 2014 _STA1 , 2014 _STA3 , 2014 _STA4 . In examples where the AP can signal the RDG in the DL MU-PCA data frame, the AP can choose not to send CTS or G-CTS. STAs in the UL MU-PCA STAs, if they have UL frames to transmit, either immediately over the assigned channel, or after some time of DL MU-PCA frame, with some IFS delay, MU-PCA transmission can be started. All STAs in the UL MU-PCA group send uplink packets to the AP via the assigned channel.

Referring to FIG. 20, the AP can wait for a further SIFS interval 2010 after the longest UL data packet 2018 _STA1 ends, and informs the reception of UL packets 2018 _STA1 , 2018 _STA3 , 2018 _STA4. In order to do so, an ACK frame 2020 _AP can be transmitted. In the example, the ACKs encoded together are all channels 218 _{1. . . 4} or on primary channel 218 ₁ only. The ACK frame 2020 _AP is _responsible for all channels 218 _{1. . . 4} or only on the primary channel 218 ₁ can also be implemented as a BA or multi-user ACK, or the AP can send the BA if the STA requests them using a BAR.

  In the example, the UL MU-PCA portion of the combined DL / UL or combined UL / DL MU-PCA transmission is any UL packet that one or more STAs in the UL MU-PCA group should transmit. If not, it can have mixed delay requirements as described above, as well as a single UL MU-PCA transmission. As described above for single DL and single UL MU-PCA sessions, acknowledgments may be implemented with ACK, BA, or multi-user ACK. APs and STAs can individually request an acknowledgment by sending a BAR and can receive a BA as a response. The AP can also send a multi-user ACK to the group of STAs to return an acknowledgment for the UL MU-PCA data frame.

  In the DL-only, UL-only, or combined UL / DL MU-PCA scheme, if one or more data packet transmissions fail, the failed data packet may need to be retransmitted. Different possible retransmission methods may be used. In an example, a DL or UL packet may be maintained at the top of the transmit buffer, on the next transmission opportunity, in a one-to-one unicast transmission, or a subsequent DL, UL, or combined DL / UL MU. -It can be retransmitted by PCA transmission. Depending on the length of the packet, a long or short retransmission timer may be counted up each time the packet is retransmitted. If the retransmission timer reaches a threshold, the packet can be discarded. In another example, G-RTS, G-CTS, G-Poll, and / or G-ACK so that there is sufficient time to retransmit the DL or UL MU-PCA packet over the allocated bandwidth. By setting the duration field, the medium can be reserved long enough. The NAV setting may be canceled by receiving an ACK packet sent to convey receipt of a DL, UL MU-PCA packet.

  STAs and APs in the BSS can inform capabilities and preferences for MU-PCA prior to MU-PCA transmission and reception. For example, the AP may include a probe response or any other type of frame in the beacon, an indicator that the AP is capable of MU-PCA. Such an indicator may also be implemented as several indicators for capabilities, for example, one indicator may be used for capabilities for UL MU-PCA and / or another indicator may be DL MU. -Can be used for capacity for PCA. In another example, there may be four indicators: DL MU-PCA capable, UL MU-PCA capable, DL SU-PCA capable, or UL MU-PCA capable. The MU-PCA capability indicator may be included in any existing or new field, such as in any management or control frame, or any other type of frame, or in a MAC or PLCP header.

  Similarly, a STA may, for example, UL and DL MU-PCA, or UL and / or SU in a probe request, association request, or other management or control frame, or other type of frame, or in a MAC or PLCP header. -One or more indicators for PCA can be used to inform the capability for MU-PCA as well. APs and STAs can signal MU-PCA preferences. The MU-PCA capability indicator may be included in any existing or new field, such as in a management, control, or IE in other types of frames.

  The AP MU-PCA preference (DL and / or UL) may include any of the following items: The AP MU-PCA preferences can include MU-PCA channel related information including, for example, the number of channels available in the MU-PCA, or the location of the MU-PCA channel. The location information shall be the location of the primary channel, for example, identified by any of the following parameters, ie, among other parameters, by frequency band, channel number, center frequency, and / or bandwidth: Can do. The location information can be, for example, any of the following parameters: frequency band, channel number, offset relative to primary channel or reference channel or frequency, center frequency, and / or bandwidth, among other parameters. MU-PCA non-primary channel location identified by.

  The AP MU-PCA preference can also include MU-PCA selection. For example, in MU-PCA transmissions, STAs may be assigned to transmit or receive over one or more channels or even over the entire bandwidth. In this case, the example of SU-PCA selection is one of the following: PHY layer aggregation only, MAC layer aggregation only, hybrid PHY / MAC layer aggregation, continuous aggregation only, and / or non-continuous aggregation possible Can be included. If only PHY layer aggregation is selected, the AP may transmit one MAC frame (including, for example, A-MPDU or A-MSDU) MU-PCA transmission on one or more continuous or non-contiguous channels. Within the STA can only send / receive from the STA. If only MAC layer aggregation is selected, the AP may send multiple MAC frames (eg, including A-MPDU or A-MSDU) in a MU-PCA transmission with each MAC frame modulated on one channel. Thus, transmission to the STA / reception from the STA is possible. If hybrid PHY / MAC layer aggregation is selected, the AP modulates one or more MAC frames (eg, including A-MPDU or A-MSDU) onto one or more continuous or non-contiguous channels Within a MU-PCA transmission with each MAC frame, it can only be transmitted to / received from the STA. If only continuous aggregation is selected, the AP can only enable aggregation of continuous channels in MU-PCA transmission. If non-continuous aggregation is enabled, the AP can allow not only continuous channels but also non-continuous channels to be aggregated.

  The AP MU-PCA preference is a MU-PCA group that can indicate the maximum number of STAs that can belong to the MU-PCA group, or in other words, the maximum number of STAs that can participate in the MU-PCA at a given time. The maximum size can also be included.

  The STA MU-PCA preferences (DL and / or UL) can include any of the following items: The STA MU-PCA preferences (DL and / or UL) may include MU-PCA channel related information and MU-PCA selection. The MU-PCA channel related information includes, for example, any of the following information, that is, the maximum number of channels available in the MU-PCA, the bandwidth for each MU-PCA channel, the bandwidth for the MU-PCA channel Can be dynamic or static and / or include any of the preferred DL / UL MU-PCA channels. For preferred DL / UL MU-PCA channel information, DL / UL MU-PCA channel preferences may be based on, for example, hardware implementation, capability, detected interference, and / or noise level, and the like. Thus, the preferred DL / UL MU-PCA channel location is, for example, any of the following parameters: frequency band, channel number, offset compared to primary channel or reference channel, frequency, center, among other parameters Either frequency and / or bandwidth can be used to identify in the information.

  The MU-PCA selection can include, for example, any of the following selections: SU-PCA enabled and SU-PCA selection. SU-PCA Capability can indicate whether the STA can perform SU-PCA. In the case of SU-PCA selection, for MU-PCA transmissions, STAs may be assigned to transmit or receive over one or more channels or even over the entire bandwidth. The SU-PCA selection may include, for example, any of the following selections, that is, only PHY layer aggregation only, MAC layer aggregation only, hybrid PHY / MAC layer aggregation, continuous aggregation only, or non-continuous aggregation is possible. it can.

  If only PHY layer aggregation is selected, the STA may transmit one MAC frame (including A-MPDU or A-MSDU) in a MU-PCA transmission that is modulated on one or more continuous or non-contiguous channels. , Can only send to / receive from another STA. If only MAC layer aggregation is selected, the STA may transmit multiple MAC frames (eg, including A-MPDU or A-MSDU) in a MU-PCA transmission with each MAC frame modulated on one channel. Thus, transmission to another STA and reception from another STA can be performed. If hybrid PHY / MAC layer aggregation is selected, the STA modulates one or more MAC frames (eg, including A-MPDU or A-MSDU) onto one or more continuous or non-contiguous channels Within a MU-PCA transmission with each MAC frame, it can only be sent to / received from another STA. If only continuous aggregation is selected, the STA can only enable aggregation of continuous channels in MU-PCA transmission. If non-continuous aggregation is enabled, the STA can allow not only continuous channels but also non-continuous channels to be aggregated. In addition, the AP or STA can use any new or existing management, control, or other types of frames to signal MU-PCA capability and / or preference changes at any time.

  The WLAN PHY layer transceiver can support single user transmission over the entire frequency band, or MU-MIMO transmission where each user occupies the entire frequency band, and to distinguish users, space division multiple access ( SDMA) can be used. The PHY layer transceiver scheme described below supports multiple users, each user partially occupying a frequency band. In the following, it is assumed that the transmitter and receiver have a symmetric bandwidth. The following are examples of several types of channel aggregation based on the nature of the frequency location of the aggregated channels, which are continuous channel aggregations where the aggregated channels can be continuous in the frequency domain Aggregated channels may not be discontinuous in the frequency domain, non-contiguous channel aggregation, hybrid channel aggregation, where some of the aggregated channels may be continuous and the rest may be discontinuous . In the following, a PHY layer method is described, which can be used in any of the channel aggregation examples. The PHY layer method can be used in conjunction with any of the MAC solutions presented and described above. In order to avoid potential collisions, G-CTS can be transmitted over the respective channels by STAs to reserve transmission channels. Other STAs wishing to operate over the same channel can listen to all packets to determine if the channel is available. Upon receiving the G-RTS and G-CTS, the STA can set the NAV and have virtual carrier sense (VCS), which will be described in detail below.

  The IFFT and / or Fast Fourier Transform (FFT) size for each user may be determined by the minimum bandwidth defined or configured for the user. For example, if 1 MHz is the minimum operating bandwidth of the system, the IFFT / FFT size may be fixed at 32 corresponding to the 1 MHz bandwidth. The same rules can be applied for other systems. In another example, the IFFT / FFT size may vary depending on other system design considerations such as subcarrier size or guard period size. If several consecutive channels are assigned to one user, the AP and / or STA can also choose to operate on a wider bandwidth. If wider bandwidth is utilized, the system can have higher spectral efficiency than a system where several channels are used separately. In this scenario, the STA may be able to perform aggregation using a continuous channel and can transmit using a wider bandwidth. STAs can support different capabilities. Changes in STA behavior based on STA's associated capabilities are described in detail below. The following are examples of STA behavior that may depend on STA capability.

  In one example, the STA may be capable of channel aggregation. The STA has the capability of channel aggregation and can negotiate with the AP in advance if more data is needed from the AP. The AP can then send a G-RTS requesting the STA to send a G-CTS over multiple channels. If the aggregated channel assigned to the STA is non-contiguous, a segment analyzer can be utilized to split the data from the MAC layer into different frequency channels. Transmission and reception via each channel may be performed by the STA using procedures defined separately for each frequency channel. Depending on different channel quality, received signal-to-noise ratio (SNR), and / or transmitter / receive capability, both equivalent and / or non-equivalent MCS may be applied to the aggregated channel. In the case of an equivalent MCS, the AP or STA can perform coding and modulation on the data passed from the MAC layer, which can then be divided into different aggregated channels by a segment analyzer. In another example, the AP or STA can perform segment analysis prior to encoding and modulation. For unequal MCS, each aggregated channel can have its own MCS.

  Based on different MCS levels, the AP or STA can use a segment analyzer to split the bits from the MAC layer into different channels and perform different coding and modulation schemes. For example, channel 1 can process 16 quadrature amplitude modulation (QAM) at 1/2 code rate, channel 2 can process 4 phase shift keying (QPSK) at rate 1/2, When guaranteeing a frame error rate (FER) of 10%, the segment analyzer can divide the bits for channel 1 to be twice the bits for channel 2. In another example, the same data can be transmitted on both frequency bands (ie, channels) to better utilize frequency diversity.

FIG. 21 shows an exemplary transmission flow diagram 2100 with STAs capable of channel aggregation. In FIG. 21, it is assumed that equivalent or non-equivalent MCS can be applied. In this example, three MU-PCA STAs 2102 ₁ , ₂ , ₃ are simultaneously supported on the AP side, STA2 2102 ₂ occupies two channels 2, 3 that are discontinuously aggregated, and channel aggregation is It is assumed that it is possible. Each MU-PCA _{STA2102 1,2,3,} if the (each) data _{x 1,} x 2, _{x 3} can receive as input is required, applying the padding _{2104 1, 2, and 3} data it can. Each STA 2102 _1,2,3 can apply scrambling 2106 _1,2,3 , forward error correction (FEC) 2108 _1,2,3 , and interleave 2110 _1,2,3 to its respective input stream. STA1 2102 ₁ and STA3 2102 ₃ that do not perform channel aggregation are constellation mapping 2313 _2,3 , inverse discrete Fourier transform (IDFT) 2116 _1,3 , guard interval (GI) 2118 _1,3 , and radio frequency front, respectively. End (RF) 2120 ₁ , ₃ can be applied respectively to generate channel y ₁ and channel y ₃ .

The STA2 2102 ₂ can generate two channels in parallel using the segment analyzer 2110 ₂ , two interleavers 2112 ₂ , 2112 ₂ ′, two constellation mappers 2114 ₂ , 2114 ₂ ′, two IDFTs 2116. ₂ , 2116 ₂ ′, two GIs 2118 ₂ , 2118 ₂ ′ and two RF front ends 2120 ₂ , 2120 ₂ ′ can be applied to generate _two channels y ₂ , y ₂ ′.

In Figure 21, relative to the STA2 2102 _2, after the FEC encoding 2108 _2, before the interleaver 2112 _2, segment analyzer 2110 ₂ can be used. In another example, the segment analyzer 2110 ₂ can follow a single interleaver 2112 ₂ so that better frequency diversity can be achieved. In another example, the segment analyzer 2110 ₂ can be placed in front of the FEC encoder 2108 ₂ so that there can be an FEC encoder for each segment, with separate encoding rates and / or encoding schemes. Can be executed on each segment.

FIG. 22 shows an exemplary PHY layer scheme 2200 in which the PLCP header is transmitted over separate frequency channels. In this example, (e.g., in FIG. 21) STA2 is assigned to the channel _{218 2,3,} available data aggregation, STA1 is assigned to the channel 218 _1, STA3 are assigned to the channel 218 _4. PLCP protocol data unit _{(PPDU) 2210 STA1, 2210 STA2} , 2210 STA2 ', 2210 STA3 may be transmitted on each channel _{218 1, 2, 3, 4.} Each PPDU, for example, PPDU 2210 _STA1, may include a preamble part 2212 _STA1 and a data part 2208 _STA1, and the preamble part 2212 _STA1 includes a short training field (STF) 2202 _STA1 and a long training field (LTF) 2204 _STA1. And a signal (SIG) field 2206 _STA1 . Channels 218 ₂ , ₃ are both used by _STA2 , but can have separate PPDUs 2210 _STA2 , 2210 _STA2 '. The SIG field ₂₂₀₆ STA2 for STA2 in the _{example, 2206 STA2} 'is on channel _{218 2,3} may include using a phase rotation or can be repeated without, the same information. When using non-equivalent MCS, all MCSs can be indicated in SIG fields 2206 _STA1 , 2206 _STA2 , 2206 _STA2 ', 2206 _STA3 , and the mapping between MCS level and frequency channel is also SIG field 2206 _STA1 , 2206 _STA2 , 2206 _STA2 ′, 2206 may be transmitted in _STA3 . Separate SIG field _{2206 STA2, 2206 STA2} 'may be encoded on each channel _{218 2,3} for STA2.

When using a non-equivalent MCS, each channel 218 _{1. . . 4} can be assigned to separate MCSs. Thus, the two SIG fields 2206 _STA2 , 2206 _STA2 'transmitted on channels 218 _2,3 may be different. In another example, the SIG field 2206 _{STA2 for STA2} may be divided into a common SIG field and an individual SIG field. The common SIG field may include common information for transmission and may be transmitted on channels 218 ₂ , ₃ within SIG fields 2206 _STA2 , 2206 _STA2 '. The individual SIG field can include information for one frequency channel / band, eg, an MCS and length field for the channel / band. Individual SIG fields may be transmitted on assigned channels 218 ₂ , ₃ in 2206 _STA2 or 2206 _STA2 ', respectively.

Depending on the operating WLAN system, the preamble formats 2212 _STA1 , 2212 _STA2 , 2212 _STA2 ′, 2212 _STA3 may be different. For example, longer preambles may be applied, including (ultra) high throughput preambles or directional preambles for beamforming or MU-MIMO transmission. If the aggregated channels assigned to the STA are contiguous, the STA or AP can use the same transmission scheme as in the case of non-contiguous aggregation, or can operate with a wider bandwidth.

FIG. 23 shows an example of a DL transmission flow diagram 2300 over a hybrid aggregated channel at an AP. In the examples of FIGS. 23, 24, and 25, it is assumed that channel 1 and channel 4 are non-contiguous, while channel 2 and channel 3 are adjacent or contiguous. Three MU-PCA STA 2302 ₁ , ₂ , ₃ can transmit simultaneously. PPDU for MU-PCA STA2302 _1,3, respectively, obtained are transmitted on channel 1, 4, whereas, STA2302 ₂ is capable of channel aggregation obtained, two consecutive channels, allocated to the channel 2,3 Can thus be transmitted over a larger bandwidth.

Each MU-PCA _{STA2302 1,2,3,} if the (each) data _{x 1,} x 2, _{x 3} can receive as input is required, applying the padding _{2304 1, 2, and 3} data it can. Each MU-PCA _{STA2302 1,2,3} are each input stream, scrambling _{2306 1,2,3, FEC2308 1,2,3,} interleaving _{2310 1, 2, 3,} and constellation mapping _{2312 2,3} Can be applied. MU-PCA STA 2302 ₁ , ₃ that does not perform channel aggregation can apply IDFT 2320 ₁ , ₃ GI 2322 ₁ , and RF 2324 ₁ , ₃ , respectively, to generate signal y ₁ and signal y ₃ . The STA2 2302 _2, since the channel aggregation may be used, two IDFT2320 _2, 2320 ₂ ', two GI2322 _2, 2322 _2', and two by applying a RF front end 2324 _2, 2324 ₂ ', the two signals y ₂ and y ₂ ′ can be generated.

For STA2 2302 _2, padding bits 2304 _2, obtained is added to the input stream _{x 2,} may be passed to the scrambler 2306 _2. Scrambled bits are transferred to the FEC encoding to FEC2308 _2. Interleaver 2310 _STA2 may be applied and the interleaved bits may be passed to constellation mapping 2312 _STA2 . The generated constellation symbols may be passed to a space-time coding block (STBC) 2314. In the example, the constellation symbols may be passed directly to the spatial mapping unit 2318 without passing through the STBC 2314. The STBC 2314 may be defined in a TXVECTOR passed from the MAC layer to the PHY layer, and this information may be sent in the SIG field. After the STBC block 2314, one symbol stream can become two symbol streams 2325, 2325 ′. The first symbol stream 2325 may be passed directly to the spatial mapping unit 2318 and the second symbol stream 2325 ′ may be applied to use a cyclic shift diversity (CSD) scheme 2316. Spatial mapping unit 2318 may be applied to the two symbol streams 2325, 2325 ′. Spatial mapping unit 2318 can be, for example, a spatial domain precoding scheme. Thereafter, generic IDFT 2320 ₂ , 2320 ₂ ′, GI blocks 2322 ₂ , 2322 ₂ ′, and RF front end 2324 ₂ ′ follow for each symbol stream.

The size of IDFT 2320 ₂ , 2320 ₂ ′ utilized by STA 2302 ₂ in this example can be twice as large as the size of IDFT 2320 ₁ , ₃ of MU-PCA STA 2302 ₁ , ₃ . In addition, different transmission schemes can be applied to STA2302 _2. For example, any of the following transmission techniques may or may not be used: space-time block coding (STBC) 2314, beamforming (not shown), or other MIMO scheme not shown. Can be used. Cyclic shift diversity (CSD) 2316 may be used to apply a progressive phase or time shift to each spatial stream, which may increase the channel frequency diversity for MU-PCA. Spatial mapping unit 2318 may be used to map the encoded information into separate spatial streams. Furthermore, both equivalent and non-equivalent MCS schemes can be applied. When using unequal MCS, an additional segment analyzer can be applied to split the MAC packet. There are many possible ways to split a packet. For example, the packet may be divided into two parts, each part corresponding to a different channel (eg, channel 2, 3).

  In another example, a packet may be divided into three or more parts, each part may correspond to a predefined subchannel or subresource block, and a resource block may refer to a group of subcarriers. The resource block may be smaller than the subchannel or may be equal to the subchannel. Different MCS levels can be applied to different parts, and the MCS level can be conveyed in the SIG field. The SIG field can contain all MCS levels for the user. The mapping between MCS level and channel / resource block may also be given in the SIG field. The SIG field can be repeated through all channels, or the SIG field can be divided into a common SIG field and an individual SIG field. The common SIG field may contain common information for transmission and may be transmitted over all available channels. The individual SIG field can include information for one frequency channel / band, eg, an MCS and length field for the channel / band. The individual SIG field may be transmitted on the channel / band to which it is assigned.

When a STA aggregates multiple channels (consecutive or non-contiguous), it can interleave with a single interleaver through all channels and can also use non-equivalent MCS. One way to achieve this is as follows. Let N _BITS be the total number of bits transmitted in one aggregated Orthogonal Frequency Division Multiplexing (OFDM) symbol. N _BITS is the desired constellation in each band represented by the number of bits per constellation symbol N _{BPS, i} and the number of data carriers (N _{D, i} ) in each band i as follows: Can depend on.

For example, in 802.11, a 40 MHz channel is N _{D, 1} = 108, while a 20 MHz channel is N _{D, 2} = 52. One 40 MHz channel and one 20 MHz channel are aggregated, 40 MHz mode is used with 64 QAM (Ν _{ΒΡ S, 1} = 6 and N _{D, 1} = 108), and 20 MHz mode is used with 16 QAM (N _BPS, 2 = 4 and _{N D,} 2 = 52) _case, it is _{N BITS = 108 × 6 + 52} × 4 = 856. Thereafter, the number of columns (N _COL ) may be set for the interleaver based on N _BITS . N _COL may be a factor of N _BITS . Continuing the above example, N _COL can be 8 or 107, and 856 = 8 × 107. N _COL may be derived from simulation results for a particular channel model. The number of interleaver rows may be defined as N _ROW = N _BITS / N _COL . The index of the encoded bit before the first permutation may be represented by k, i may be the index after the first permutation and before the second permutation, and j is the second After replacement, it can be the index just before modulation mapping. Thus, the first permutation of the interleaver is
i = N _ROW (k mod N _COL ) + floor (k / N _COL ) k = 0, 1,. . . , N _BITS -1 Formula 2
Can be defined.

The second permutation may be performed separately on each band depending on the MCS used in that band. Ν _{TOT, i} is assumed to be ＴＯ _{TOT, i} = ND _{, j} N _{BPS, j} and is the total number of bits per OFDM symbol in each band. In that case,

and

It is.

  If there are multiple spatial streams, the interleaver described above may be used on each spatial stream, and additional rotations may be applied between different spatial streams. The deinterleaver can reverse the above permutation on each band and spatial stream, if any.

FIG. 24 shows an exemplary flow 2400 of PPDU transmission over a channel that includes a hybrid aggregated channel. STA1 in FIG. 23, STA2, and STA3 _is, PPDU2401 _{STA1, 2401 STA2,} and _{2401 STA3} transmits, the PPDU2401 _STA1 and _{2401 STA3} for STA1 and STA3, respectively, resulting transmitted on channel 218 ₁ and 218 _4, On the other hand, STA2 is capable of channel aggregation and can be assigned to two consecutive channels 218 ₁ , ₂ , and therefore transmits on a larger bandwidth. PPDU 2401 _STA1 and 2401 _STA3 can include STF 2402 _STA1 and 2402 _STA3 , LTF2404 _STA1 and 2404 _STA3 , SIG2406 _STA1 and 2406 _STA3 , and data 2408 _STA1 and 2408 _STA3 (with padding added), respectively. The STF can be used for, among other things, the start of packet detection and coarse time and frequency offset correction. The LTF can be used for, among other things, precise time and frequency offset correction, and channel estimation. The SIG field can carry a PHY layer header.

PPDU 2401 _STA2 containing aggregated data transmitted on two channels 218 _{2, 3} may include STF 2402 _{STA 2} , LTF 2404 _{STA 2} , LTF 2410 _{STA 2} , SIG 2406 _{STA 2} , and data 2408 _{STA 2} (with padding added). it can. PPDU2401 _STA2 may have two _{LTF2404 STA2, 2410 STA2,} second _{LTF2410 STA2,} if two data streams are transmitted to the STA2, it may be used for channel estimation.

Is transmitted using normal bandwidth, when compared to STA1 and PPDU2401 _STA1 and _{2401 STA3} for STA3, the PPDU2401 _STA2 for _STA2, and PLCP header including STF2402 _{STA2, LTF2404 STA2,} SIG field _{2406 STA2,} Both data 2408 _STA2 for STA2 are transmitted using a wider bandwidth. The transmission shown in this exemplary flow 2400 may be protected by the GRTS / GCTS protocol. Thus, unintended STAs within the same BSS or overlapping BSS (OBSS) may not need to understand MU-PCA transmissions. In the example of FIG. 24, an unintended STA may not understand the preamble transmitted on channels 2182 and ₃ if it cannot operate on a wider bandwidth. An unintended STA can detect the GRTS / GCTS sequence sent before the data session and set the NAV accordingly. However, it is also possible to provide additional protection at the PHY layer by changing the PLCP header format.

FIG. 25 shows another example flow 2500 of PPDU transmission over a channel that includes a hybrid aggregated channel. Channel 218 _{1. . . 4} is the same as that in FIG. 24 except that the legacy PLCP header information for STA2 can be transmitted separately on channels 218 _{2 and 3} (PPDU2501 _STA1 and PPDU2401 _STA1 is the same, PPDU2501 _STA2 is the same as PPDU4501 _{STA2, PPDU2501 STA13} is the same as the PPDU2401 _STA3). The legacy PLCP header information includes a legacy STF (LSTF) 2502 _STA2 , a legacy LTF (LLTF) 2504 _STA2, and a legacy SIG (LSIG) 2506 _STA2 . Accordingly, FIG. 25 shows an exemplary variation of the PLCP header format of FIG. 24, since a set of STF, LTF, and SIG fields are repeatedly transmitted on channel 2 and channel 3, It may be detectable by non-MU-PCA users and other OBSS users.

  The above example described in FIGS. 23-25 shows a solution for communicating with STA2 / user 2 using a wider bandwidth. The system spectral efficiency can be higher when using wider bandwidth, so the scheduler can know if channel aggregation is done continuously, and keep users with heavy traffic loads continuously. You can try to assign to the aggregated channel. In another example, STA2 / User 2 can communicate using a normal single channel bandwidth, but can occupy two normal channels. The IFFT / IDFT size for STA2 / User2 can be the same as for STA1 and STA3. In this case, a segment analyzer can be utilized (similar to the example of FIGS. 21 and 22) to split the traffic into two parts. Depending on channel quality and STA feedback capability, both equivalent and non-equivalent MCS may be applied. This solution may not be as efficient as STA2 / user 2 operating with a wider bandwidth, but may be easier to implement.

  In one example, the STA may be capable of MIMO. A MIMO scheme may be used for MU-PCA transmission. The MIMO transmission can include, without limitation, space division multiplexing (SDM), STBC, beamforming, CDD, or MU-MIMO. MIMO transmission may depend on the number of antennas available at the transmitter and receiver sides. For example, a MIMO system using M transmit antennas and N receive antennas supports up to min (M, N) spatial data streams for single user MIMO (SU-MIMO) or MU-MIMO. it can. With existing WiFi specifications and standards, the AP / STA can have knowledge about the number of antennas available on both the transmitter and receiver sides. Therefore, an appropriate MIMO scheme can be selected. In MU-PCA transmission, the antenna on the AP side needs to be shared with multiple users, so knowing the number of antennas available on the AP side is not enough for the STA to select an appropriate MIMO scheme. Sometimes. Furthermore, the number of users supported by MU-PCA transmission may change over time. Thus, it may not be possible for the AP to advertise its MIMO capability and the number of MU-PCA users supported at one time, and all MU-PCA transmissions may follow the same setup. In the example, the AP can assign an MCS to the STA. In this way, the AP can determine the appropriate MIMO scheme for the STA, eg, in the PLCP header (eg, in the SIG field), MCS, and (defining channel / spatial stream assignments for multiple users). You can advertise the location of multiple users. In another example, this information may be exchanged prior to MU-PCA transmission.

  In another example of STA behavior, the STA may not be capable of channel aggregation. In this case, the STA may be assigned at most one channel and one bandwidth. MU-PCA or SU-PCA can use the same transceiver method. Both equivalent and non-equivalent MCS can be applied, as well as different MIMO schemes can be applied.

  If a set of channels is used in either SU-PCA or MU-PCA, the transmit power used for each channel may be different. This can be due to regulations established by local or national administration, or it can be due to observed channel conditions that can vary widely. In the case of SU-PCA, the channels in the aggregated channel set may experience different interference, fading, etc. For MU-PCA, the channel between the AP and various STAs may vary due to distance, shadow fading, etc. in addition to interference and fast fading. Non-equivalent MCS can be used to adapt to the condition of each channel and to achieve higher throughput.

Modified TXVECTOR and RXVECTOR may be used to support unequal MCS and / or unequal transmit power for each of a set of consecutive or non-contiguous channels or frequency segments, examples of which are as follows: Explained. TXVECTOR and RXVECTOR can be designed as vectors of the form
TXVECTOR = [TXVECTOR_Common, TXVECTOR_0, TXVECTOR_1,. . . , TXVECTOR_N] Equation 5
RXVECTOR = [RXVECTOR_Common, RXVECTOR_0, RXVECTOR_1,. . . , RXVECTOR_N] Equation 6
Here, TXVECTOR_Common and RXVECTOR_Common may include parameters that apply to all channels or all frequency segments used in SU-PCA or MU-PCA, where TXVECTOR_i and RX_VECTOR_i, 0 <i <N , May include parameters specific to the i th channel or frequency segment. The i th channel can be of any bandwidth and can consist of continuous and non-contiguous frequency segments.

  For example, in an 802.11af network, TXVECTOR_i and RXVECTOR_i are in operation modes defined by the 802.11af standard, such as TVHT_W, TVHT_2W, TVHT_4W, TVHT_W + W, and TVHT_2W + 2W operation modes. Parameters for the channel can be included.

  Alternatively, TXVECTOR_i and RXVECTOR_i may include parameters for the i-th channel with 2W bandwidth in TVHT_2W, TVHT_4W, and TVHT_2W + 2W modes of operation. Some parameters that may be included in TXVECTOR_Common and RXVECTOR_Common are shown in Table 5, where Y and N indicate the presence (Y) or absence (N) of the corresponding parameter.

  Table 6 shows some parameters that may be included in TXVECTOR_i and RXVECTOR_i, where Y and N indicate the presence (Y) or absence (N) of the corresponding parameter in TXVECTOR_i and RXVECTOR_i , MU indicates the presence of the MIMO mode.

  All the parameters in Table 6, for example Parameter_i, 0 <i <N, may be parameters specific to the i th channel or frequency segment. The i th channel can be of any bandwidth and can consist of continuous or non-contiguous frequency segments. For example, in an 802.11af network, Parameter_i may include parameters for an i th channel with bandwidth W in TVHT_W, TVHT_2W, TVHT_4W, TVHT_W + W, and TVHT_2W + 2W modes of operation. Alternatively, Parameter_i may be a parameter for the i-th channel with 2W bandwidth in TVHT_2W, TVHT_4W, and TVHT_2W + 2W operating modes.

  The STA / AP can achieve support for non-equivalent MCS and non-equivalent transmission power for SU-PCA and MU-PCA by using PLCP transmission and reception procedures such as the examples described below; The STA / AP can gain access to the channel as described above. The transmission of the PPDU is PHYTXSTART. After receiving a request (TXVECTOR) primitive, it can be initiated by PLCP, PHY-TXSTART. The TXVECTOR element for the request primitive is as described above.

  For each channel or frequency segment, PLCP has the following physical medium dependent (PMD) primitives for configuring PMD: PMD_TXPWRVLVL. request and PMD_TX_PARAMEERS. A parameter can be issued by request. TXPPWRLVL and TX_PARAMETERS may be unique for each channel or frequency segment. The PLCP uses PMD_TXSTART (TXVECTOR).. To initiate transmission of the PLCP preamble on each of the channels or frequency segments defined by the elements in the TXVECTOR parameter. A request primitive can be issued. After the PLCP preamble transmission is initiated on all channels or frequency segments, the PHY layer entity can begin data scrambling and data encoding. The encoding method for the data field of each packet on each channel or frequency segment can be based on the FEC_CODING_i, CH_BANDWIDTH_i, NUM_STS_i, STBC_i, MCS_i, and NUM_USERS_i parameters of TXVECTOR as described above. The data is a series of PHY-DATA .. data for each data frame on each channel or frequency segment issued by the MAC. request (DATA) primitive, and PHY-DATA. It can be exchanged between the MAC layer and the PHY layer through a confirm primitive.

  The PLCP reception procedure can support unequal MCS and unequal transmit power in SU-PCA and MU-PCA. When PMD receives the transmitted PLCP preamble on all channels or frequency segments, PMD_RSSI. The indication can report the received signal strength for each of the channels or frequency segments to the PLCP. The PMD primitive PMD_RSSI may be issued to the PLCP that can record the received RSSI value, RSSI_i, for each channel or frequency segment. PLCP is a PHY-RXSTART. The most recently received RSSI_i value can be included in the indication (RXVECTOR) primitive.

  PHY-CCA. After the indication (BUSY, channel-list) is issued, the PHY entity can start receiving training symbols on all channels or frequency segments. If correct signaling and mode is detected from the preamble on all channels or frequency segments, PHY-RXSTART. An indication (RXVECTOR) primitive may be issued. The RXVECTOR associated with the primitive can include any of the parameters specified above. The PHY layer can further decode PSDU on all channels or frequency segments according to RXVECTOR. The received bits of the PSDU include a series of PHYDATA .. for each PSDU on the channel or frequency segment. It can be assembled into octets, decoded, and presented to the MAC using indication (DATA) primitive exchange. After receiving the last bit of the last PSDU octet, as well as possible padding and tail bits, on all channels or frequency segments, the receiver can return to the RX IDLE state.

  The PHY layer may have some limitations on the operating bandwidth. For example, some 802.11ah devices may be able to aggregate multiple channels when participating in MU-PCA, but the bandwidth of each operating channel may be limited to 2 MHz, while AP On the side, three channels (each with 1 MHz bandwidth) can be aggregated and assigned to this MU-PCA user. In this example, at the MAC layer, the AP can prepare two separate MAC packets, which are sent to the user. At the PHY layer, the AP can assign one MAC packet to one of the aggregated channels with 2 MHz bandwidth and assign the rest of the MAC packet to another channel with 1 MHz bandwidth be able to. This can be achieved using layer mapping.

  FIG. 26 is a flow diagram of an example method 2600 that uses layer mapping 2604 to map N MAC packets 2602 (for N or fewer users) to K layers 2606. Each layer can process the assigned data stream independently. For example, each layer may have a separate encoding and modulation scheme and also a separate MIMO scheme. Different interleavers (not shown) can be defined for each layer, or one interleaver can be used across several layers. The layer mapping 2604 can map, for example, one MAC packet to one layer, multiple MAC packets to one layer, and one MAC packet to multiple layers, or from multiple MAC packets to multiple layers. Comprehensive mapping can be performed. After layer processing, the packet may be passed to spatial / frequency mapping 2608, which may further map multiple layers to multiple spatial streams or frequency bands. Method 2600 may be applied to all previously described PHY designs.

  The following example relates to MU-PCA enabled by using transmit / receive with asymmetric bandwidth. The use of asymmetric bandwidth can have a flexible architecture and the number of users that it can support by MU-PCA is not limited by the number of antennas. Furthermore, it can simplify or reduce the cost of WLAN STA or AP / STA design. The use of MU-PCA over continuous and / or discontinuous channels through widely separated frequencies can be difficult for asymmetric bandwidth. For example, UL MU-PCA STAs sent to the AP at the same time may have to be close at the received power level at the AP to avoid perspective problems. Also, simultaneous transmission of UL MU-PCA packets may have to arrive at the AP within a guard interval (GI) so that the AP can correctly decode each packet.

  The 802.11af and 802.11ah specifications can be considered as clocked down versions of the 802.11ac specification. As a result, the guard interval (GI) can be 8 microseconds long, which assumes a UL MU-PCA packet assuming a 6.67 microsecond round trip time (RTT) over a 1 km coverage range. May be long enough to allow for time alignment. Note also that the Timing Synchronization Function (TSF) timer can currently maintain 1 microsecond accuracy. Under the assumption of TSF timer accuracy and GI duration, a single receiver is used at the AP instead of multiple receivers for each of the frequency segments to simultaneously receive packets from multiple STAs. obtain.

  The channelization proposed in the 802.11ah framework can make the use of transmit / receive with asymmetric bandwidth a reasonable possibility. Current or near future RF techniques can use a single RF chain to cover the entire bandwidth expected for 802.11ah and other sub-1 GHz technologies.

  The MAC and PHY layer methods utilize the above observations to handle transmission / reception using asymmetric bandwidth. The MAC layer scheme for single UL, single DL, combined UL / DL, and retransmission scheme may be similar to that described above for transmission / reception using asymmetric bandwidth. However, since transmission / reception uses asymmetric bandwidth, additional changes in the MAC layer can be performed as described below. A PHY layer method for supporting MU-PCA with asymmetric bandwidth is also presented. One example is to provide a MU-PCA that uses a relatively wideband AP and a relatively narrowband STA. In another example, a MU-PCA using multiple narrowband combined APs and a narrowband STA is provided to the STA. In these examples, AP and non-AP hardware may be changed.

  The exemplary methods, signaling, and procedures described below provide MU-PCA to multiple STAs simultaneously via multiple continuous or non-contiguous channels that are widely separated in frequency. These methods can enable MU-PCA using transmit / receive with asymmetric bandwidth, for example, in 802.11ah or similar technology, which ensures accurate timing to align UL MU-PCA transmissions. MU-PCA can also be enabled in other existing WLAN systems.

  A MAC design to support MU-PCA using transmit / receive with asymmetric bandwidth can consist of two parts described below, which are single DL, single UL, and combined It is a MAC system that enables DL / UL MU-PCA and STA group management. Single UL, Single DL, Combined UL / DL, MAC layer scheme for UL / DL MU-PCA, and retransmission scheme use transmit / receive with symmetric bandwidth as described above It is the same as that presented in the case of MU-PCA.

  STAs participating in MU-PCA (using transmission / reception with asymmetric bandwidth) can be organized into groups in a predetermined or ad hoc manner for UL, DL, or combined UL and DL transmission. STA grouping may be different for UL and DL. DL MU-PCA group management is similar to that described above for MU-PCA using transmission / reception with symmetric bandwidth. STAs are grouped together according to one or a combination of several different criteria, such as operating channel width, similar received power at the AP, QoS priority, synchronization, and buffered packet length, among other criteria. obtain. If well tuned, a group of STAs may be able to use some portion of the available frequency bandwidth up to the entire bandwidth.

  In the case of UL MU-PCA group management, simultaneous UL MU-PCA transmissions can arrive at the AP with similar received power in the GI. Grouping may be performed using a received signal strength indication (RSSI) indicator for each STA that may already be available at the AP. The AP can record the RSSI for each packet received from the STA. The AP may be, for example, [0 dB, N dB], [N + 1 dB, 2 × N dB],. . . , [M × N + 1 dB, (m + 1) × N dB]. The value of N may depend on the tolerance of the AP receiver. For example, the STA can enter the RSSI interval or bin n if 90% of the L most recent RSSI values are classified into the interval [(n−1) × N + 1 dB, n × N dB].

  All STAs included in the same bin can be candidates to be classified into the same UL MU-PCA group. Since RSSI may be a rough estimate of the distance between the STA and the AP, it may allow UL MU-PCA packets sent from the group at the same time to arrive at the AP within the GI. STAs in the same RSSI bin may be selected according to various criteria, for example, selecting one of the following: STA with the largest channel width first, STA with the smallest channel width first, or the like By either selecting STAs with QoS requirements, further selections can be made to form a group that can occupy the maximum available channels. In addition, various signaling, mechanisms, and procedures for group monitoring and maintenance, as well as for STA grouping, can be applied to enable MU-PCA in various WLAN systems.

The PHY layer procedure for MU-PCA using transmit / receive with asymmetric bandwidth is described below. In some cases, the AP can perform relatively wideband transmission / reception, and the STA can perform relatively narrowband transmission / reception. The PHY layer method can lower the hardware cost on the AP side, increase the complexity on the STA side, and / or make the MU-PCA more flexible. Assuming an OFDM-based WLAN system, the subcarrier frequency spacing can be a constant for different channel bandwidths. Thus, if the channel bandwidth is doubled, the IFFT / FFT size utilized for the OFDM system can also be doubled. For example, in 802.11ah, a 2 MHz channel bandwidth mode may require 64-point IFFT / FFT at the PHY layer, and a 4 MHz channel bandwidth mode may require 128 point IFFT / FFT. Assume subcarrier spacing is represented by delta _F.

The AP aggregates N channels, each channel having a center frequency f _n , nε {1, 2,. . . , N}, assuming that the bandwidth is BW _n , the bandwidth BW of the aggregated channel is

Can be.

  The bandwidth spanned by the entire aggregation is

It is.

For continuous channel aggregation, BW = BW _span , while for non-continuous channel aggregation, BW <BW _span . The AP can assign the aggregated channels to K users. The IFFT / IDFT size N _FFT used in the aggregated channel is

Can be equal to For example, in 802.11ah, when the AP continuously aggregates two 1 MHz channels and one 2 MHz channel, BW = BW _span = 4 MHz. If Δ _F = 31.25 kHz, the IFFT / IDFT size N _FFT for the aggregated channel is 4000 / 31.25 = 128. In an example using non-continuous channel aggregation, BW _span = 5 MHz, while BW = 4 MHz, the IFFT / IDFT size N _FFT for this non-continuous aggregated channel is 5000 / 31.25 = 160.

  The PPDU structure and PLCP header may be modified as shown in FIGS. 27, 28, and 29. In FIG. 27, FIG. 28, and FIG. 29, the PLCP header includes a short training field (STF), a long training field (LTF), and a SIG field. The PLCP header can include a longer preamble, eg, it is a first set of STF, LTF, SIG fields for legacy or omni-directional operation, where the set of STF, LTF, SIG is In a first set of STF, LTF, SIG fields that can be transmitted weighted with omnidirectional antenna weights, and in a second set of STF, LTF, SIG fields for (ultra) high throughput or directional operation A second set of STFs, wherein a set of STFs, LTFs, SIGs can be transmitted weighted with selected antenna weights and this mode can be used for MU-MIMO transmission or beamforming transmissions, LTF and SIG fields can be included. DL and UL transceivers are described below.

In the case of a DL transmitter, the STF may be transmitted using the STF format of the minimum channel defined by the standard. In different parallel channels, the STF can be repeated with or without phase rotation. In another example, the STF may be transmitted using the same bandwidth as the rest of the packet. The LTF, SIG, and data fields may be transmitted using IFFT / IDFT size N _FFT as defined in Equation 9. Special guard intervals and / or null subcarriers (tones) may be inserted between users. Special guard / null subcarriers can be designed according to the corresponding spectral mask requirements. The location of the guard / null tone can be changed according to user allocation and user bandwidth. The LTF can be transmitted using a wideband format with guard tones. Although LTF can be used with a narrowband format, the LTF sequence can cover all data subcarriers utilized in the SIG / data portion of the packet. The SIG field is the same in each channel, can be repeated, or can be user specific or channel specific.

FIGS. 27 and 28 show examples of PHY layer schemes 2700 and 2800 in which MU-PCA users have three and two PHY layers, respectively. In FIG. 27, STA ₁ is assigned to channel 218 ₁ , STA ₃ is assigned to channels 218 ₂ and ₃ , and STA ₄ is assigned to channel 2184. The AP is responsible for each channel 218 to be aggregated _{. . .} Over _4, it performs phase rotation, or without, the STF2702 _AP, subsequently, can transmit the LTF2704 _AP, for LTF2704 _AP transmits on bandwidth combined with channel _{218 2,3.} The STAs (STA1, STA3, STA4) can transmit SIG2706 _STA1 , 2706 _STA3 , 2706 _STA4 , and data (and padding) 2707 _STA1 , 2708 _STA3 , 2708 _STA4 to the AP via their assigned channels.

In FIG. 28, STA1 is assigned to channels 218 ₁ and ₂ , and STA2 is assigned to channels 218 ₃ and ₄ . The AP is responsible for each channel 218 to be aggregated _{. . .} Over _4, performs phase rotation, or without, the STF2802 _AP, subsequently, on the combined bandwidth of the channel _{218 1, 2} and channel _{218 3,4} can transmit LTF2804 _AP. The STAs (STA1, STA3, STA4) transmit SIG2806 _STA1 , 2806 _STA2 and data (and padding) 2808 _STA1 , 2808 _STA2 via the channels assigned to each _STA .

FIG. 29 shows an example of a PHY layer scheme 2900 that uses an exemplary STF format for MU-PCA transmission. In FIG. 29, STA1 is assigned to channels 218 ₁ and ₂ , and STA2 is assigned to channels 218 ₃ and ₄ . The STF 2902 _AP may be transmitted using the same bandwidth as the rest of the packets, i.e., on the combined channels 218 ₁ , ₂ , 218 ₃ , ₄ . A concise or preamble format may be used. For example, a long preamble with a (super) high throughput or directional part (used for beamforming or MU-MIMO transmission) may be used. A long preamble can provide additional PHY protection. Similar to the example of FIG. 28, the AP can transmit an LTF 2904 _AP over the combined bandwidth of channels 218 _{1, 2} and channels 218 ₃ , ₄ . The STAs (STA1, STA3, STA4) can transmit SIG2906 _STA1 and 2906 _STA2 and data (and padding) 2908 _STA1 and 2908 _STA2 via their assigned channels.

FIG. 30 shows an exemplary PHY layer scheme 3000 that employs a PPDU that uses a long preamble to provide additional protection on MU-PCA transmission. The narrowband transmission 3002 by the _AP , including the preamble portion including the STF 3006 _AP , the LTF 3008 _AP , and the SIG field 3010 _AP , each channel 218 _{1. . .} It can be repeated on ₄ . The preamble portion corresponding to the narrowband transmission 3002 may be detected by a normal unintended STA with or without MU-PCA capability. Preamble portions corresponding to MU-PCA transmission 3004, including STF 3012 _AP and LTF 3014 _AP , may be detected by a MU-PCA capable STA. STAs (STA1, STA3, STA4) in the MU-PCA group can transmit SIG fields 3016 _STA1 , 3016 _STA3 , 3016 _STA4 and data (and padding) 3018 _STA1 , 3018 _STA3 , 3018 _STA4 , respectively. A STA that is not MU-PCA capable or unintended can know that it is a MU-PCA transmission and whether it is a potential destination or receiver for MU-PCA transmissions, Information may be carried in the SIG field 3010 _{AP for} narrowband transmission. Other variations are possible. For example, transmission of MU-PCA STF 3012 _AP and LTF 3014 _AP may be omitted, and legacy STF (LSTF) and legacy (LLTF) may be reused.

In FIGS. 27-30, the LTF 3014 _AP is shown to have the same length or duration among all MU-PCA users. This is referred to as a uniform LTF design. When using an equal LTF design, the AP can know the number of data streams assigned to each MU-PCA user, and thus the number of LTF symbols used for each MU-PCA user for channel estimation. The number can be calculated accordingly. The AP can transmit the maximum number of LTFs among all MU-PCA users. For example, STA1 can transmit one data stream and thus one LTF can be used for channel estimation. STA2 can transmit two data streams, so two LTFs can be used for channel estimation. For MU-PCA together with STA1 and STA2, the AP can send two LTFs. In this way, the AP can communicate to each user the number of data streams it has allocated and the total number of LTFs transmitted in the SIG field.

  In another example, unequal LTF may be used. Using this design, the AP can send as many LTFs as it needs. Using the above example again, the AP can transmit over one LTF-assigned channel for STA1, followed by transmission of data. The AP can transmit over a channel assigned two LTFs for STA2. In this way, the AP can communicate to each user the number of allocated data streams.

FIG. 31 shows an exemplary transmission flow diagram 3100 on the AP side. A layer may correspond to a data stream, a MAC packet, a user, or other possible partition of data. Following layer mapping 3102, M layers 3104 _{1. . .} Each of _M may be encoded and modulated separately using separate layer processing. In other words, each layer can have its own MCS and MIMO scheme. In FIG. 31, each layer 3104 <b> _{1. . . M} is, for example, a padding component 3106 _{. . .} And _M, scrambler 3108 _{1. . .} And _M, FEC component 3110 _{1. . .} And _M, the interleaver 3112 _{1. . .} And _M, constellation mapper 3114 _{1. . .} And _M, STBC3116 _{1. . .} And _M, a plurality of cyclic shift diversity (CSD) component 3118 _{1. . . M} can be included. In the example, if one MAC packet is prepared for unicast to the user and there is one user, the PHY layer can divide the MAC packet into multiple layers. The frequency segment mapper 3120 can map M layers to K frequency segments or channels, where each segment is an IDFT 3122 _{. . .} GI component 3124 which can be processed using _{K1 . . . K} can apply a guard interval between users.

  For example, multiple MAC packets can be prepared so that each user can have one MAC packet or multiple MAC packets. An AP can map MAC packets to multiple layers by mapping multiple MAC packets to one layer or by mapping one MAC packet to multiple layers. Coding and modulation may be performed on each layer, after which frequency segment mapping can map the layers to frequency segments. Multiple layers can be mapped to one frequency segment, or one layer can be mapped to multiple frequency segments. In another example, an AP can broadcast or multicast a single MAC packet to multiple users via multiple channels. A MAC packet may be iteratively mapped to multiple layers and then to multiple frequency segments.

For DL receivers, the STA may need to know the AP's transmission bandwidth (BW _span ) and subchannel assignment. This exchange of information may occur within the MAC handshake (eg, with grouping configuration signaling) prior to MU-PCA transmission. The STA can use at least the same sampling rate as the AP. Instead of using the same wideband filtering, the STA can apply narrowband filtering. For WiFi signals, the STA can utilize the STF on its frequency band for automatic gain control (AGC), coarse frequency offset, and coarse timing detection. A wideband FFT of size N _FFT can be performed and based on the shortened or full size LTF (which can depend on whether the wideband LTF is transmitted or the narrowband LTF is transmitted) Timing frequency correction and channel estimation may be applied. Following the LTF, the SIG field and data portion can be decoded normally. The FFT size used on the STA side can be N _FFT defined in Equation 9.

For UL transmitters, the STA may need to know the AP's receive bandwidth (BW _span ) and subchannel assignments. This exchange of information may occur within the MAC handshake (eg, with grouping configuration signaling) prior to setting up the MU-PCA transmission. The STF transmitted by each STA can be in a narrowband format, while the LTF transmitted by each STA can be a shortened wideband LTF or a narrowband format LTF. When using narrowband LTF, the LTF sequence in the frequency domain can cover all data subcarriers by the corresponding transmitting STA.

FIG. 32 shows an exemplary transmission flow diagram 3200 on the STA side that may be used to prepare the data portion of the PPDU for transmission. FIG. 32 shows one layer, layer 3204 _m, but more than one layer may be assigned to a STA, and each layer may have a separate MCS. Following layer mapping 3202, layer 3204 _m can do any of the following: padding 3206 _m , scrambler 3208 _m , FEC 3210 _m , interleaver 3212 _m , constellation mapper 3214 _m , or STBC 3216 _m. Then, any one of the CSD3218 _m can be applied to the signal (see, for example, the description of FIG. 31) to generate k channels. Any of these elements can be omitted, for example, STBC3216 _m can be omitted. The k channels may be provided to a frequency segment mapper 3220 that can map M layers to K frequency segments or channels, after which IDFT 3222 _{1. . . K} and GI remover 3224 _{1. . . K} may be applied to each of the k channels.

In the example of FIG. 32, one layer is mapped to one frequency segment. In another example, multiple layers may be mapped to one frequency segment, or one layer may be mapped to multiple frequency segments. The IFFT / IDFT size used on the STA side can be N _FFT as defined in Equation 9.

FIG. 33 shows an exemplary transmission flow diagram 3300 at the AP side where the AP may operate as a receiver for UL communications. The MU-PCA may be set up at the MAC layer, but at the PHY layer, the assigned frequency segments x ₁ . . . At _xk , one or more packets may be expected to arrive at the same time. Each segment x1 _{. . .} For each _k, GI removal 3302 _{1. . . k} and inverse discrete Fourier transform (IDFT) 3304 _{1. . .} Following _k , a frequency segment demapping 3306 converts the frequency domain data signal into a plurality of layers 3308 _{1. . .} can be mapped to _m . Each layer 3308 _{1. . . m} can apply single channel receiver processing to the corresponding layer of data, which can be either: MIMO detection 3310 _{. . . m,} demodulation 3312 _{1. . . m,} deinterleaver 3314 _{1. . . m,} the descrambler 3318 _{1. . . m,} and padding removal 3320 _{1. . .} Any of _m can be included. Layer demapper 3322 is layer 3308 _{. . . m} outputs can be mapped to MAC packets. This scheme may be applied with or without a MIMO scheme (ie, MIMO detection 3310 _1... M). MIMO schemes can include, for example, without limitation, spatial multiplexing, space-time block codes, and beamforming.

  The MCS level can be indicated in the SIG field. A large SIG field may be defined, which may include all MCS levels used for STA / user. A mapping between MCS levels and channel / resource blocks may also be given in the SIG field. This “large” SIG field may be transmitted or repeated over all channels for the STA / user. In another example, the SIG field may be divided into a common SIG field and an individual SIG field. The common SIG field may include common information for transmission and may be transmitted over the entire bandwidth / channel for the STA / user. The individual SIG field can include information for one frequency channel / band, eg, an MCS and length field for the channel / band. The dedicated SIG field may be transmitted on the assigned channel / band.

  Other examples of PHY designs and procedures for MU-PCA using transmit / receive with asymmetric bandwidth are described. The STA may need to know the frequency allocation information. Each user can utilize his own Fourier transform, or some users can share a relatively wideband Fourier transform. In one example, for a user / STA with one channel or multiple continuously aggregated channels, the IFFT / FFT size may be defined by the channel bandwidth allocated to this user / STA. In an example, a STA / user may be assigned two consecutively aggregated 1 MHz channels, in which case the IFFT / FFT size may be 64. In another example, for a 1 MHz channel, the IFFT / FFT size utilized may be 32. In another example, for users with two or more non-continuously aggregated channels, separate Fourier transforms or one Fourier transform may be used.

  Two or more users can share a continuously aggregated channel. In the example, assume that channel 1 can be separated (ie, non-contiguous) from continuous channels 2, 3, and 4. Assume that channel 1 can be assigned to user 1, channel 2 and channel 3 can be assigned to user 2, and channel 4 can be assigned to user 3. In the example, separate Fourier transforms can be used for different users. In the above example, user 2 can utilize a Fourier transform that covers channel 2 and channel 3, while user 3 can utilize a Fourier transform that covers channel 4. In another example, one wideband Fourier transform may be used for continuous channels. For example, in the above example, STA / users 2 and 3 can utilize one broadband Fourier transform.

  In another example, different Fourier transforms can be utilized for different STAs / users. In this case, each STA / user can execute its own transmission function block. After configuring the OFDM signal in the time domain, the signal can be shifted to the assigned frequency segment. The frequency shift can be performed in baseband or in the RF domain. If the frequency shift is performed in the RF domain, the signal processing may be the same as for MU-PCA using transmission / reception with symmetric bandwidth described above.

FIG. 34 shows an exemplary transmission flow diagram 3400 on the AP side for DL transmission. Following layer mapping 3402, each layer 3404 _{1. . . M} is, any of the following, namely, padding 3406 _{1. . . M,} scrambler 3408 _{1. . . M,} FEC3410 _{1. . . M,} interleaver 3412 _{1. . . M,} constellation mapping 3414 _{1. . . M,} STBC3416 _{1. . . M,} and CSD3418 _{1. . .} Any of _M can be applied to the signal. Either it is obtained omitted of these elements, for example, STBC3416 _{1. . . M} may be omitted.

In the example of FIG _{. . .} In the _M, space mapping 3420 _{1. . . M} can generate a separate signal for each user, and the transmit flow can be applied to each user's signal, which is IDFT4322 _{. . . M} and GI insertion 3424 _{1. . . M} can be included. Then, each layer 3401 _{1. . .} In the _M, frequency shifter 3426 _{1. . . M} can shift the time domain signal into k assigned frequency segments / channels. The frequency shift can be performed in baseband or in the RF domain. For each transmit antenna, a total 3428 of time domain signals for all users may be transmitted. The STF and LTF can be transmitted using the same bandwidth as the data.

  For DL receiver designs, the STA may need to know the frequency segment assigned to it and can use a single channel receiver on that frequency segment. For UL transmitter designs, the STA may need to know the frequency segment assigned to it and can use the transmitter on that frequency segment. In the UL receiver design example, on the AP side, the received signal may be down-converted into K streams and detection / decoding may be performed. In another example, the entire signal may be downconverted to baseband with the following center frequency:

Here, F _{C, MAX} = max (F _{c, k} ), F _{C, MIN} = min (F _{c, k} ), and F _{c, k} is the center frequency of the kth user. Narrowband filtering may be applied on each frequency band, followed by other reception procedures. This scheme can be applied with or without the MIMO scheme. MIMO schemes include, without limitation, spatial multiplexing, space-time block codes, and beamforming, among others.

  Above, a PPDU can be sent within a collision-free period, eg, when the MAC mechanism has set NAV protection for all periods, and other STAs do not need to understand certain SIG fields in the PPDU. Good. If a non-MU-PCA STA may require detection of the SIG field of the MU-PCA PPDU, the PLCP header may be changed, or other changes may be made. For example, MU-PCA STF and LTF transmissions can be removed or reduced, and LSTF and LLTF can be reused. As with symmetric transmission / reception, equivalent and non-equivalent MCS can be supported in this scheme. The MCS level can be indicated in the SIG field.

  One user may be assigned to multiple MAC packets due to operational channel bandwidth limitations. Also, some users may share the same MAC packet (eg, broadcast packet or multicast packet). The PHY layer may be able to handle all kinds of MAC packets for different scenarios. A general transmission block flow may be applied to the asymmetric bandwidth. A single user may be considered a special case of MU-PCA transmission. In this case, in single user transmission, the layer mapping can map one or a plurality of MAC packets to one layer. A set of encoding / modulation and MIMO schemes can then be applied to this layer. In another example, layer mapping can map one or more MAC packets to multiple layers. In another example, separate encoding / modulation and MIMO schemes may be applied to multiple layers.

  Embodiment

  1. A method for use in a wireless transmit / receive unit (WTRU).

  2. 2. The method of embodiment 1 comprising receiving a request to send (RTS) message from an access point (AP) via a channel associated with the WTRU.

  3. The method of any preceding embodiment comprising an RTS message indicating that the AP is ready to send multiple data messages.

  4). The method of any preceding embodiment, comprising an RTS message indicating that the AP is ready to send a plurality of data messages to a plurality of WTRUs.

  5. 9. The method of any preceding embodiment comprising an RTS message indicating that the AP is ready to send multiple data messages simultaneously over multiple channels to multiple WTRUs.

  6). The method of any preceding embodiment, further comprising transmitting a first ready to send (CTS) message.

  7). The method of any preceding embodiment, further comprising sending a first ready to send (CTS) message to the AP.

  8). 9. The method as in any preceding embodiment, further comprising transmitting to the AP a first ready to send (CTS) message over a channel associated with the WTRU.

  9. 9. The method as in any of the embodiments 6-8, wherein the CTS message indicates that the WTRU is ready to receive via a channel associated with the WTRU.

  10. The method of any preceding embodiment, further comprising receiving a data message of the plurality of data messages.

  11. 11. The method of embodiment 10 further comprising receiving a data message from the plurality of data messages from the AP.

  12 12. The method of embodiment 11 further comprising receiving a data message of the plurality of data messages from the AP via a channel associated with the WTRU.

  13. The method of any preceding embodiment, further comprising sending an acknowledgment (ACK) message.

  14 14. The method of embodiment 13, further comprising sending an acknowledgment (ACK) message to the AP.

  15. 15. The method of embodiment 14 further comprising sending an acknowledgment (ACK) message to the AP over a channel associated with the WTRU.

  16. [0069] 16. The method as in any of the embodiments 14-15, wherein the ACK message includes more fragment bits.

  17. 16. The method of embodiment 15 wherein the more fragment bit is set to be “1” if the WTRU has uplink (UL) data to send to the AP.

  18. 18. The method of embodiment 17 further comprising receiving a second CTS message from the AP when the more fragment bit is set to 1 and the WTRU has uplink data to send to the AP.

  19. 19. The method of embodiment 18, further comprising receiving a second CTS message from the AP via a channel associated with the STA.

  20. The method of any preceding embodiment, further comprising transmitting uplink (UL) data.

  21. 21. The method of embodiment 20, further comprising transmitting uplink (UL) data to the AP.

  22. 23. The method of embodiment 21 further comprising transmitting uplink (UL) data to the AP via a channel associated with the STA.

  23. 90. A method as in any preceding embodiment, wherein the channels associated with the WTRU include two or more channels.

  24. 24. The method as in any of the embodiments 6-23, wherein transmitting the first CTS message is simultaneous with CTS message transmission by a plurality of WTRUs.

  25. 25. The method as in any of the embodiments 13-24, wherein the step of transmitting the ACK message is simultaneous with transmission of the ACK message by a plurality of WTRUs.

  26. 26. The method as in any of the embodiments 5-25, wherein at least two of the plurality of channels have different bandwidths.

  27. 27. The method as in any one of embodiments 2-26, wherein the RTS message is a group RTS (G-RTS) message.

  28. 28. The method as in any of the embodiments 6-27, wherein the first CTS message is a group CTS (G-CTS) message.

  29. 29. The method as in any of the embodiments 13-28, wherein the ACK message is a group ACK (G-ACK) message.

  30. 119. A method as in any preceding embodiment, wherein the WTRU is an Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless local area network (WLAN) station (STA).

  31. A method used in an access point (AP).

  32. 32. The method of embodiment 31 comprising transmitting to a station (STA).

  33. 33. The method as in any of the embodiments 31-32, comprising transmitting to a station (STA) via a channel associated with the STA.

  34. 34. The method as in any of the embodiments 31-33, comprising sending a request for transmission (RTS) message to a station (STA) via a channel associated with the STA.

  35. 35. The method of embodiment 34, wherein the RTS message indicates that the AP is ready to send multiple data messages.

  36. 36. The method as in any of the embodiments 34-35, wherein the RTS message indicates that the AP is ready to send multiple data messages to multiple WTRUs.

  37. 37. The method as in any of the embodiments 34-36, wherein the RTS message indicates that the AP is ready to send a plurality of data messages over a plurality of channels to a plurality of WTRUs.

  38. 38. The method as in any one of embodiments 34-37, wherein the RTS message indicates that the AP is ready to send multiple data messages simultaneously over multiple channels to multiple WTRUs.

  39. 39. The method as in any one of embodiments 31-38, further comprising receiving a first ready to send (CTS) message.

  40. 410. The method as in any one of embodiments 31-39, further comprising receiving a first ready to send (CTS) message from the STA.

  41. 41. The method as in any of the embodiments 31-40, further comprising receiving a first ready to send (CTS) message from a STA via a channel associated with the STA.

  42. 42. The method as in any of the embodiments 39-41, wherein the first CTS message indicates that the STA is ready to receive via a channel associated with the STA.

  43. 43. The method as in any of the embodiments 31-42, further comprising transmitting a plurality of data messages to the STA.

  44. 44. The method of embodiment 43, wherein sending a plurality of data messages to the STA is performed via a plurality of channels.

  45. 45. The method as in any of the embodiments 31-44, further comprising receiving an acknowledgment (ACK) message.

  46. 46. The method as in any of the embodiments 31-45, further comprising receiving an acknowledgment (ACK) message from the STA.

  47. 47. The method as in any one of embodiments 31-46, further comprising receiving an acknowledgment (ACK) message from the STA via a channel associated with the STA.

  48. 48. The method as in any of the embodiments 45-47, wherein the ACK message includes more fragment bits.

  49. 49. The method of embodiment 48, wherein the more fragment bits are set to be “1” when the STA has uplink (UL) data to send to the AP.

  50. 50. The method as in any one of embodiments 31-49, further comprising transmitting to the STA when the more fragment bit is set to 1 and the STA has uplink data to transmit to the AP.

  51. 51. The method of embodiment 50, wherein transmitting to the STA includes transmitting a second CTS message over a channel associated with the STA.

  52. 50. The method as in any one of embodiments 31-49, further comprising receiving uplink (UL) data from a STA via a channel associated with the STA.

  Although the solution described herein considers 802.11 specific protocols, the solution described herein is not constrained to this scenario and is equally applicable to other wireless systems. Please understand that.

  Although features and elements have been described above in specific combinations, those skilled in the art will appreciate that each feature or element can be used alone or in any combination with other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware contained in a computer readable medium that is executed by a computer or processor. Examples of computer readable media include electronic signals (transmitted over a wired or wireless connection) and computer readable storage media. Examples of computer readable storage media are read only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disk and removable disk, magneto-optical media, and CD-ROM. Including but not limited to optical media such as discs and digital versatile discs (DVDs). A processor associated with the software may be used to implement a radio frequency transceiver for use with a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims (20)

Indicates that the access point (AP) is ready to send multiple data messages to multiple WTRUs simultaneously via multiple channels associated with a wireless transmit / receive unit (WTRU) A receiver configured to receive a request to send (RTS) message from the AP;
Via the channel associated with the WTRU, a first ready to send (CTS) message indicating that the WTRU is ready to receive via the channel associated with the WTRU; A transmitter configured to transmit to the AP, and
The receiver is configured to receive a data message of the plurality of data messages from the AP via the channel associated with the WTRU;
The transmitter is configured to transmit an acknowledgment (ACK) message to the AP via the channel associated with the WTRU, the ACK message including more fragment bits, and the more fragment bits Is set to “1” on condition that the WTRU has uplink (UL) data to transmit to the AP. Provided that the more fragment bit is set to 1 and the WTRU has uplink data to transmit to the AP;
The receiver is further configured to receive a second CTS message from the AP via the channel associated with the STA;
The WTRU of claim 1, wherein the transmitter is further configured to transmit the uplink (UL) data to the AP via the channel associated with the STA.   2. The WTRU of claim 1 wherein the channel associated with the WTRU includes two or more channels.   The WTRU of claim 1, wherein the transmitter is configured to transmit the first CTS message simultaneously with CTS message transmission by the plurality of WTRUs. The WTRU of claim 1, wherein the transmitter is configured to transmit the ACK message simultaneously with ACK message transmission by the plurality of WTRUs.   The WTRU of claim 1 wherein at least two of the plurality of channels have different bandwidths.   The RTS message is a group RTS (G-RTS) message, the first CTS message is a group CTS (G-CTS) message, and the ACK message is a group ACK (G-ACK) message. The WTRU of claim 1, wherein:   The WTRU of claim 1, wherein the WTRU is an Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless local area network (WLAN) station (STA). A method for use in a wireless transmit / receive unit (WTRU) comprising:
A transmission request (RTS) indicating that an access point (AP) is ready to simultaneously transmit multiple data messages via multiple channels to multiple WTRUs via a channel associated with the WTRU. ) Receiving a message from the AP;
Via the channel associated with the WTRU, a first ready to send (CTS) message indicating that the WTRU is ready to receive via the channel associated with the WTRU; Sending to the AP;
Receiving a data message of the plurality of data messages from the AP via the channel associated with the WTRU;
Transmitting an acknowledgment (ACK) message to the AP via the channel associated with the WTRU, wherein the ACK message includes more fragment bits, the more fragment bits being transmitted by the WTRU; A method, comprising: a step set to “1” on condition that there is uplink (UL) data to transmit to the AP. Provided that the more fragment bit is set to 1 and the WTRU has uplink data to transmit to the AP;
Receiving a second CTS message from the AP via the channel associated with the STA;
10. The method of claim 9, further comprising: transmitting the uplink (UL) data to the AP over the channel associated with the STA.   10. The method of claim 9, wherein the channel associated with the WTRU includes two or more channels.   10. The method of claim 9, wherein the step of transmitting the first CTS message is simultaneous with CTS message transmission by the plurality of WTRUs.   10. The method of claim 9, wherein the step of transmitting the ACK message is simultaneous with ACK message transmission by the plurality of WTRUs.   The method of claim 9, wherein at least two of the plurality of channels have different bandwidths.   The RTS message is a group RTS (G-RTS) message, the first CTS message is a group CTS (G-CTS) message, and the ACK message is a group ACK (G-ACK) message. The method of claim 9, wherein:   10. The method of claim 9, wherein the WTRU is an Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless local area network (WLAN) station (STA). A transmission request indicating that the access point (AP) is ready to simultaneously transmit multiple data messages via multiple channels to multiple WTRUs via the channel associated with the station (STA) A transmitter configured to send an (RTS) message to the STA;
Via the channel associated with the STA, a first ready to send (CTS) message indicating that the STA is ready to receive via the channel associated with the STA; A receiver configured to receive from the STA;
The transmitter is configured to transmit the plurality of data messages to the STA via the plurality of channels;
The receiver is configured to receive an acknowledgment (ACK) message from the STA via the channel associated with the STA, the ACK message including more fragment bits, and the more fragment bits Is set to “1” on condition that the STA has uplink (UL) data to transmit to the AP. On condition that the more fragment bit is set to 1 and the STA has uplink data to send to the AP,
The transmitter is further configured to transmit a second CTS message to the STA via the channel associated with the STA;
The AP of claim 17, wherein the receiver is further configured to receive the uplink (UL) data from the STA via the channel associated with the STA. A method for use in an access point (AP), the method comprising:
A request to send (RTS) indicating that the AP is ready to send multiple data messages over multiple channels simultaneously to multiple WTRUs via a channel associated with a station (STA) Sending a message to the STA;
Via the channel associated with the STA, a first ready to send (CTS) message indicating that the STA is ready to receive via the channel associated with the STA; Receiving from the STA;
Transmitting the plurality of data messages to the STA via the plurality of channels;
Receiving an acknowledgment (ACK) message from the STA via the channel associated with the STA, wherein the ACK message includes more fragment bits, the more fragment bits being transmitted by the STA; A method, comprising: a step set to “1” on condition that there is uplink (UL) data to transmit to the AP. Under the condition that the more fragment bit is set to 1 and the STA has uplink data to transmit to the AP,
Sending a second CTS message to the STA via the channel associated with the STA;
The method of claim 19, further comprising: receiving the uplink (UL) data from the STA over the channel associated with the STA.